People v. Valencia

IN THE SUPREME COURT OF
CALIFORNIA

THE PEOPLE,
Plaintiff and Respondent,
v.
JOSE LUIS VALENCIA,
Defendant and Appellant.

S250218

Fifth Appellate District
F072943

Kern County Superior Court
LF010246B
________________________________________________________

THE PEOPLE,
Plaintiff and Respondent,
v.
EDGAR ISIDRO GARCIA,
Defendant and Appellant.

S250670

Fifth Appellate District
F073515

Kern County Superior Court
LF010246A
 July 1, 2021

Justice Corrigan authored the opinion of the Court, in which
Chief Justice Cantil-Sakauye and Justices Liu, Cuéllar,
Kruger, Groban, and Jenkins concurred.
 PEOPLE v. VALENCIA*
S250218

Opinion of the Court by Corrigan, J.

This case involves allegations of active gang participation
(Pen. Code, § 186.22, subd. (a)) and gang enhancements (Pen.
Code, § 186.22, subd. (b)) attached to other offenses. The
charges require proof that a gang’s members have engaged in “a
pattern of criminal gang activity” (Pen. Code, § 186.22, subd.
(f)), defined, in part, as the commission of two or more
enumerated offenses (Pen. Code, § 186.22, subd. (e)). We hold
that the commission of such crimes, also known as predicate
offenses, must be proven by independently admissible evidence.
Under the authority of People v. Sanchez (2016) 63 Cal.4th 665
(Sanchez), such proof may not be established solely by the
testimony of an expert who has no personal knowledge of facts
otherwise necessary to satisfy the prosecution’s burden. The
judgment of the Court of Appeal, reaching the same conclusion,
is affirmed.
I. BACKGROUND
Early on the morning of August 24, 2014, Jose B. and
Alejandro P. sat on the tailgate of a truck at a carwash in the
City of Arvin. Multiple shots were fired. One round struck Jose
in the leg and others hit the truck tires. Coincidentally, an
officer on patrol near the carwash happened to see a pickup
driving slowly with its lights off, then saw seven to 10 muzzle

*
Consolidated with People v. Garcia (S250670).

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 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

flashes coming from the front passenger window. Shining a
light on the pickup, the officer saw defendant Jose Luis Valencia
behind the wheel and defendant Edgar Isidro Garcia in the
passenger seat. An hour-long vehicle chase ensued, during
which Garcia threw something from the truck’s window. The
cylinder of a revolver was later recovered in that vicinity.
Defendants were ultimately arrested, and gunshot residue was
found on the front passenger door of the pickup.
Both defendants were charged with two counts of
attempted murder, assault with a firearm, and active street
gang participation. 1 Garcia was also charged with shooting
from a vehicle.2 Valencia was charged with evading an officer
and knowingly allowing a passenger to shoot from the truck. 3
Gang and firearm enhancements were attached to the various
charges.4
Arvin Police Officer Ryan Calderon testified as a gang
expert. A nine-year department veteran, he had specialized in
gang enforcement for five and a half years and had personally
investigated about 200 crimes involving the Arvina 13 gang.
Calderon testified about the gang, describing its monikers,
graffiti, tattoos, colors, and territory, which included the

1
Penal Code sections 187, subdivision (a), 189, subdivision
(a), 664, subdivision (a), 245, subdivision (a)(2), 186.22,
subdivision (a).
2
Penal Code section 26100, subdivision (c).
3
Vehicle Code section 2800.2, subdivision (a); Penal Code
section 26100, subdivision (b).
4
Penal Code sections 186.22, subdivision (b)(1), 12022.5,
subdivision (a), 12022.53, subdivisions (c), (d), (e)(1), 12022.55,
12022.7, subdivision (a).

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Opinion of the Court by Corrigan, J.

carwash. Arvina 13’s primary felonious activities include
shootings, assaults, burglaries, and drug sales.
In Officer Calderon’s opinion, Valencia and Garcia were
Arvina 13 gang members, based on their tattoos and police
contacts. In response to a hypothetical question, Calderon
testified that defendants’ conduct benefitted Arvina 13 by
creating community fear and gang notoriety. Calderon also
related the facts of three predicate offenses committed by Arvina
13 gang members: a 2008 assault by Jose Arredondo, a 2010
assault by Adam Arellano, and a 2013 attempted robbery and
assault by Orion Jimenez. Calderon’s only knowledge of these
offenses came from conversations with other officers and a
review of police reports. Certified copies of court documents
related to the convictions in each case were admitted into
evidence, including the pleadings and court minute orders.
Defendants’ first trial ended when the jury hung on almost
all charges.5 A second jury convicted defendants of the
remaining allegations. Both men were sentenced to extended
prison terms.6 The Court of Appeal held that some of the
expert’s testimony about the predicate offenses constituted
inadmissible hearsay. It reversed the active gang participation

5
The jury convicted Valencia of evading an officer but
deadlocked on the remaining charges as to both defendants.
6
The court sentenced Garcia to two terms of 15 years to life
on the two attempted murder counts, plus 25 years to life for
firearm discharge causing great bodily injury, and 20 years for
firearm discharge, consecutive, staying the remaining counts.
Valencia received two life terms for attempted murder and the
same terms of 25 years to life and 20 years for firearm discharge
by a principal in a gang offense, with the remaining charges
stayed.

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 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

and enhancement allegations, as well as Valencia’s firearm
enhancements attached to those allegations, and otherwise
affirmed the judgments. (People v. Valencia (July 10, 2018,
F072943) [nonpub. opn.]; People v. Garcia (July 10, 2018,
F073515) [nonpub. opn.].)7 We granted the Attorney General’s
petitions for review and consolidated these two cases for
decision.8
II. DISCUSSION
The Attorney General argues the gang expert’s recitation
of hearsay describing the circumstances of the three predicate
offenses constituted background information about which the
expert could properly testify. To resolve this issue, we examine
the statutory scheme covering gang allegations, our decisions in
Sanchez and People v. Veamatahau (2020) 9 Cal.5th 16
(Veamatahau), and Court of Appeal decisions that have
previously addressed the question.

7
The Court of Appeal remanded both matters to the trial
court for retrial on the reversed allegations or, if the People elect
not to retry them, for resentencing. The trial court was ordered
to exercise its discretion whether to strike Garcia’s firearm
enhancements under newly enacted Senate Bill No. 620 (2017–
2018 Reg. Sess.) (Stats. 2017, ch. 682, §§ 1–2), and Valencia was
to be allowed to make a record of factors relevant at a future
youth offender parole hearing (Pen. Code, §§ 3051, 4801, subd
(c); see People v. Franklin (2016) 63 Cal.4th 261, 283–284).
8
We initially granted the People’s petitions for review in
these cases and held them for People v. Perez (2020) 9 Cal.5th 1
(Perez), which concluded a defendant’s failure to object did not
forfeit a Sanchez claim in a case predating that decision. (See
id. at pp. 7–14.) After the Perez decision, we consolidated these
matters and sought briefing on the current predicate offense
issue.

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 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

A. The STEP Act
In 1988, the Legislature enacted the California Street
Terrorism Enforcement and Prevention Act (STEP Act or Act;
Pen. Code, § 186.20 et seq.) to eradicate “criminal activity by
street gangs.” (People v. Loeun (1997) 17 Cal.4th 1, 4 (Loeun).)
Underlying the STEP Act was the Legislature’s finding that
“California is in a state of crisis which has been caused by
violent street gangs whose members threaten, terrorize, and
commit a multitude of crimes against the peaceful citizens of
their neighborhoods.” (Pen. Code, § 186.21, 2d par.) The
Legislature sought to balance the “constitutionally protected
rights of freedom of expression and association” (id., 1st par.)
with the need to protect all Californians from the burden of fear,
intimidation and physical harm caused by gang violence, which
it found presents “a clear and present danger to public order and
safety” (id., 1st par.). The Act was specifically structured to
protect both free association and public safety. (See People v.
Rodriguez (2012) 55 Cal.4th 1125, 1133–1135 (lead opn. of
Corrigan, J.) (Rodriguez).)
As relevant here, the STEP Act created a substantive
offense of active participation “in any criminal street gang” (Pen.
Code, § 186.22, subd. (a)), and a sentencing enhancement for a
felony committed “for the benefit of, at the direction of, or in
association with any criminal street gang” (Pen. Code, § 186.22,
subd. (b)(1)). (See Rodriguez, supra, 55 Cal.4th at p. 1130 (lead
opn. of Corrigan, J.); see also id. at p. 1130, fn. 5 (lead opn. of
Corrigan, J.).) The Act defines such a gang as “any ongoing
organization, association, or group of three or more persons,
whether formal or informal, having as one of its primary
activities the commission of one or more [enumerated offenses],
having a common name or common identifying sign or symbol,

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Opinion of the Court by Corrigan, J.

and whose members individually or collectively engage in, or
have engaged in, a pattern of criminal gang activity.” (Pen.
Code, § 186.22, subd. (f).) A “ ‘pattern of criminal gang activity’ ”
is separately defined as “the commission of, attempted
commission of, conspiracy to commit, or solicitation of, sustained
juvenile petition for, or conviction of two or more [enumerated]
offenses, provided at least one of these offenses occurred after
the effective date of this [Act] and the last of those offenses
occurred within three years after a prior offense, and the
offenses were committed on separate occasions, or by two or
more persons . . . .” (Pen. Code, § 186.22, subd. (e).)9 The
offenses comprising a pattern of criminal gang activity are
referred to as predicate offenses. (See Loeun, supra, 17 Cal.4th
at p. 4.) We use the term “commission” in this opinion to include
the broader statutory inclusion of the “attempted commission of,
conspiracy to commit, or solicitation of, sustained juvenile
petition for, or conviction” of a predicate offense. (Pen. Code,
§ 186.22, subd. (e).)
Penal Code section 186.22, subdivision (e) does not state
that a predicate offense must be committed by a gang member.
However, that requirement derives from the definition of a
“ ‘criminal street gang,’ ” which includes proof that the gang’s
“members individually or collectively engage in, or have engaged

9
The original STEP Act was an urgency measure that went
into effect on September 26, 1988. (Stats. 1988, ch. 1242, § 3;
see People v. Gardeley (1996) 14 Cal.4th 605, 626 (Gardeley),
disapproved on another ground in Sanchez, supra, 63 Cal.4th at
p. 686, fn. 13.) Citations here are to the Act which became
effective on January 1, 1993. (Stats. 1989, ch. 930, § 5.1.) Those
provisions, by their terms, are repealed as of January 1, 2022,
to be replaced by an identical provision on that date. (See Stats.
2016, ch. 887, § 1; Stats. 2017, ch. 561, § 179.)

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Opinion of the Court by Corrigan, J.

in, a pattern of criminal gang activity.” (Pen. Code, § 186.22,
subd. (f), italics added.) It follows, then, that the proof of a
predicate offense must establish that a member of a defendant’s
alleged gang was involved in its commission. 10 Taken together
the statutory scheme requires proof that gang members
committed at least two predicate offenses within the statutory
timeframe. Such proof will generally require evidence of who
committed the crime and when they did so, as well as evidence
of their gang membership and the nature of the crimes. How
those particular facts are proven lies at the heart of this case.
B. Sanchez and Veamatahau
In Sanchez, the defendant was arrested and found to
possess a gun and drugs packaged for sale. (Sanchez, supra, 63
Cal.4th at p. 671.) He was convicted of drug and firearm
offenses with attached gang enhancements (Pen. Code, § 186.22,
subd. (b)(1)) and the substantive offense of active gang
participation (Pen. Code, § 186.22, subd. (a)). (Sanchez, at pp.
671, fn. 1, 673.) On appeal, he argued that the gang expert was
erroneously permitted to testify about five prior contacts
Sanchez had with police. The expert had no personal knowledge

10
The requirement that a gang member be involved in a
predicate offense is to be distinguished from new allegations
that the charged defendant actively participated in a gang (Pen.
Code, § 186.22, subd. (a)) or committed a gang enhancement
(Pen. Code, § 186.22, subd. (b)). A defendant need not be a gang
member for those charged allegations to be proven, so long as all
statutory elements are satisfied. (See Rodriguez, supra, 55
Cal.4th at p. 1130 (lead opn. of Corrigan, J.); People v. Valdez
(2012) 55 Cal.4th 82, 132; Pen. Code, § 186.22, subd. (i).)
However, before a conviction can be relied on in the future as
evidence of a predicate offense, there must be evidence that the
perpetrator was a gang member.

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Opinion of the Court by Corrigan, J.

of these contacts but read about them in police reports and other
sources. (Id. at p. 673.) The expert was permitted to testify as
to the particulars of the police contacts, as described in those
documents, to explain the basis of his opinion that Sanchez was
a gang member and committed the charged offenses for the
gang’s benefit. (See id. at p. 683; Gardeley, supra, 14 Cal.4th at
pp. 618–620.) If offered for the truth of their content, statements
repeated from those sources would constitute hearsay. The jury
was told, however, that the testimony was not admitted for its
truth but only to explain the basis for the expert’s opinion.
(Sanchez, at p. 684.)
In Crawford v. Washington (2004) 541 U.S. 36 (Crawford),
the United States Supreme Court held that the confrontation
clause of the federal Constitution generally bars the admission
of what it termed “testimonial” hearsay when offered by the
prosecution against a criminal defendant without a showing of
witness “unavailability and a prior opportunity for cross-
examination.” (Crawford, at p. 68.) It clarified, however, that
out-of-court statements not offered for the truth of their content
are not hearsay and do not impinge upon the confrontation
right. (Id. at pp. 59–60, fn. 9.) Sanchez addressed “whether
facts an expert relates as the basis for his opinion are properly
considered to be admitted for their truth.” (Sanchez, supra, 63
Cal.4th at p. 674.) Sanchez arose at the intersection of the
hearsay rule, the holdings in Crawford and its progeny, and the
evidentiary rules applicable to expert testimony.

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Hearsay is an out-of-court statement offered to prove the
truth of its content.11 Ordinarily, hearsay is inadmissible unless
it falls under a recognized exception. (Evid. Code, § 1200, subd.
(b).) In addition, lay witnesses may only testify about matters
within their personal knowledge. (Evid. Code, § 702, subd.
(a).)12 In the case of experts, both of these general rules are
applied with greater latitude. “A person is qualified to testify as
an expert if he has special knowledge, skill, experience, training,
or education sufficient to qualify him as an expert on the subject
to which his testimony relates.” (Evid. Code, § 720, subd. (a).)
“An expert may express an opinion on ‘a subject that is
sufficiently beyond common experience that the opinion of an
expert would assist the trier of fact.’ (Evid. Code, § 801, subd.
(a).) In addition to matters within their own personal
knowledge, experts may relate information acquired through
their training and experience, even though that information
may have been derived from conversations with others, lectures,
study of learned treatises, etc.” (Sanchez, supra, 63 Cal.4th at
p. 675.) “[A]n expert’s testimony concerning his general
knowledge, even if technically hearsay, has not been subject to
exclusion on hearsay grounds.” (Id. at p. 676.)

11
The statute defines hearsay as “evidence of a statement
that was made other than by a witness while testifying at the
hearing and that is offered to prove the truth of the matter
stated.” (Evid. Code, § 1200, subd. (a).)
12
“ ‘Personal knowledge’ means a present recollection of an
impression derived from the exercise of the witness’ own
senses.” (Cal. Law Revision Com. com., 29B pt. 2A West’s Ann.
Evid. Code (2019 ed.) foll. § 702, p. 416.) “ ‘Perceive’ means to
acquire knowledge through one’s senses.” (Evid. Code, § 170.)

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Sanchez contrasted general knowledge about facts
accepted in the expert’s field with “case-specific facts about
which the expert has no independent knowledge.” (Sanchez,
supra, 63 Cal.4th at p. 676.) “Case-specific facts are those
relating to the particular events and participants alleged to
have been involved in the case being tried.” (Id. at p. 676; see
further discussion of what constitutes “case-specific facts” in pts.
C & D, post.) “Generally, parties try to establish the facts on
which their theory of the case depends by calling witnesses with
personal knowledge of those case-specific facts. An expert may
then testify about more generalized information, even if derived
from hearsay, to help jurors understand the significance of those
case-specific facts. An expert is also allowed to give an opinion
about what those facts may mean. The expert is generally not
permitted, however, to supply case-specific facts about which he
has no personal knowledge.”13 (Sanchez, at p. 676.)
Exploration of an expert’s opinion based on case-specific
facts outside the expert’s personal knowledge can still be
accomplished through the use of hypothetical questions: “An
examiner may ask an expert to assume a certain set of case-
specific facts for which there is independent competent evidence,
then ask the expert what conclusions the expert would draw

13
Education and training often involve statements and
writings conveyed by teachers and other experts. In addition,
however, expert witnesses may acquire knowledge through their
own experimentation, observations and personal experience.
(See Evid. Code, § 720, subds. (a), (b); Simons, Cal. Evidence
Manual (2021) § 4:1, pp. 318–321.) Like any other witness,
experts can relate what they have personally observed and that
testimony would not be hearsay. It can, of course be challenged
by the opponent, but its admission would not implicate Sanchez
or the broader hearsay rule.

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Opinion of the Court by Corrigan, J.

from those assumed facts. If no competent evidence of a case-
specific fact has been, or will be, admitted, the expert cannot be
asked to assume it. The expert is permitted to give his opinion
because the significance of certain facts may not be clear to a lay
juror lacking the expert’s specialized knowledge and
experience.” (Id. at pp. 676–677.)
Although “[a]t common law, the treatment of an expert’s
testimony as to general background information and case-
specific hearsay differed significantly” (Sanchez, supra, 63
Cal.4th at p. 678), that treatment evolved after enactment of the
Evidence Code in 1965: “Evidence Code section 801, subdivision
(b) provides that an expert may render an opinion ‘[b]ased on
matter (including his special knowledge, skill, experience,
training, and education) perceived by or personally known to the
witness or made known to him at or before the hearing, whether
or not admissible, that is of a type that reasonably may be relied
upon by an expert in forming an opinion upon the subject to
which his testimony relates, unless an expert is precluded by law
from using such matter as a basis for his opinion.’ (Italics
added.) Similarly, Evidence Code section 802 allows an expert
to ‘state on direct examination the reasons for his opinion and
the matter (including, in the case of an expert, his special
knowledge, skill, experience, training, and education) upon
which it is based, unless he is precluded by law from using such
reasons or matter as a basis for his opinion.’ ” (Sanchez, at p.
678.) Where an expert relied upon out-of-court statements to
explain the bases of an opinion, “[c]ourts [had] created a two-
pronged approach to balancing ‘an expert’s need to consider
extrajudicial matters, and a jury’s need for information
sufficient to evaluate an expert opinion’ so as not to ‘conflict with
an accused’s interest in avoiding substantive use of unreliable

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hearsay.’ ” (Id. at p. 679, quoting People v. Montiel (1993) 5
Cal.4th 877, 919.) The jury would be given a limiting instruction
that “matters admitted through an expert go only to the basis of
his opinion and should not be considered for their truth.”
(Montiel, at p. 919.) The trial court retained discretion to
exclude the evidence under Evidence Code section 352 if it
concluded the probative value was substantially outweighed by
the probability that the jury would ignore the limiting
instruction and “improperly consider it as independent proof of
the facts recited therein.” (People v. Coleman (1985) 38 Cal.3d
69, 91.)
Sanchez disapproved the Montiel procedure. (Sanchez,
supra, 63 Cal.4th at p. 686, fn. 13.) “When an expert relies on
hearsay to provide case-specific facts, considers the statements
as true, and relates them to the jury as a reliable basis for the
expert’s opinion, it cannot logically be asserted that the hearsay
content is not offered for its truth. In such a case, ‘the validity
of [the expert’s] opinion ultimately turn[s] on the truth’
[citation] of the hearsay statement.” (Sanchez, at pp. 682–683.)
Sanchez observed that juries are instructed to decide “ ‘whether
information on which the expert relied was true and accurate’ ”
(id. at p. 684, quoting CALCRIM No. 332), and “[w]ithout
independent competent proof of those case-specific facts, the
jury simply ha[s] no basis from which to draw such a
conclusion.” (Sanchez, at p. 684.) “Once we recognize that the
jury must consider expert basis testimony for its truth in order
to evaluate the expert’s opinion, hearsay and confrontation
problems cannot be avoided by giving a limiting instruction that
such testimony should not be considered for its truth. If an
expert testifies to case-specific out-of-court statements to
explain the bases for his opinion, those statements are

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necessarily considered by the jury for their truth, thus rendering
them hearsay. Like any other hearsay evidence, it must be
properly admitted through an applicable hearsay exception.
Alternatively, the evidence can be admitted through an
appropriate witness and the expert may assume its truth in a
properly worded hypothetical question in the traditional
manner.” (Id. at p. 684, fn. omitted.)
Sanchez concluded the gang expert related case-specific
facts.14 “[His] case-specific testimony as to defendant’s police
contacts was relied on to prove defendant’s intent to benefit the
Delhi gang when committing the underlying crimes to which the
gang enhancement was attached. [He also] recounted facts
contained in the police reports and STEP notice to establish
defendant’s Delhi membership. While gang membership is not
an element of the gang enhancement [citation], evidence of
defendant’s membership and commission of crimes in Delhi’s
territory bolstered the prosecution’s theory that he acted with
intent to benefit his gang, an element it was required to prove.”
(Sanchez, supra, 63 Cal.4th at pp. 698–699; see id. at p. 685.)
In Veamatahau, the defendant was charged with
possessing contraband pills. The question at trial was whether

14
An out-of-court statement about case-specific facts may or
may not involve “testimonial hearsay,” depending on who made
the statements, under what circumstances, and for what
purpose. (Cf. Ohio v. Clark (2015) 576 U.S. 237, 243–251; Davis
v. Washington (2006) 547 U.S. 813, 821–832; Crawford, supra,
541 U.S. at pp. 51–59; People v. Cage (2007) 40 Cal.4th 965, 984;
Simons, Cal. Evidence Manual (2020) § 2:115.) One import of
the Sanchez holding, however, is that out-of-court statements
offered to prove case-specific facts are hearsay regardless of any
testimonial character. (See Sanchez, supra, 63 Cal.4th at pp.
684–686.)

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the recovered pills contained the controlled substance
alprazolam. An expert compared markings he saw on the pills
“against a database containing descriptions of
pharmaceuticals.” (Veamatahau, supra, 9 Cal.5th at p. 22.)
Asked about the identification process, the expert testified that
the approach he employed was generally accepted in the
scientific community. He elaborated on cross-examination that
“when ‘there’s a controlled substance in the tablet, the FDA
[(Food and Drug Administration)] requires companies to have a
distinct imprint on those tablets to differentiate it from any
other tablets. The FDA regulates that. [¶] And if there’s a tablet
that has — in this case GG32 — or 249 [as an imprint] — you
can look that up. And it’s going to tell you that it contains
alprazolam, 2 milligrams. And that’s — we trust that, all those
regulations being in place, to say that there’s alprazolam in
those tablets.’ ” (Id. at p. 23.) Based on this database search,
the expert opined the pills contained alprazolam. (Ibid.)
Veamatahau concluded that the expert’s testimony about what
he read from the database was background information. “[The
expert’s] statement concerning what the database ‘tell[s] you’
related general background information relied upon in the
criminalist’s field. The facts disclosed by the database, and
conveyed by [the expert], are ‘about what [any generic] pills
containing certain chemicals look like.’ [Citation.] The
database revealed nothing about ‘the particular events . . . in the
case being tried,’ i.e., the particular pills that Sergeant Simmont
seized from defendant. [Citation.] Any information about the
specific pills seized from defendant came from [the expert’s]
personal observation (that they contained the logos ‘GG32 — or
249’) and his ultimate opinion (that they contained alprazolam),
not from the database. In short, information from the database

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is not case specific but is the kind of background information
experts have traditionally been able to rely on and relate to the
jury.” (Id. at p. 27.)
Veamatahau clarifies that the distinction between
background information and case-specific facts can depend, in
part, on what the evidence, considered independently, is offered
to prove. The expert’s testimony about the contents of the
database, and expert reliance on it, was offered to prove that all
pills with a given imprint contain alprazolam. That testimony,
though hearsay, related background information. His opinion
was offered to prove that the defendant’s pills, those at issue in
the current prosecution, contained alprazolam. The markings
on the defendant’s pills were case-specific facts. The expert was
permitted to testify about them because his own observation of
the markings provided personal knowledge. The jury was
entitled to consider the expert-provided background
information, even though hearsay, along with his personal
observations and opinion to determine whether the pills the
defendant possessed contained the controlled substance. (See
discussion, post.)
C. Distinguishing Background Information from Case-
specific Facts
In gang cases, drawing the line of demarcation between
background and case-specific information can present
challenges, as reflected by the different conclusions drawn by
the Courts of Appeal regarding predicate offenses. Several cases
have held that predicate offense evidence is merely background
similar to other kinds of information about gangs, like their
territory, symbols, and operations, that are generally accepted
as true by experts in the field. (See People v. Bermudez (2020)
45 Cal.App.5th 358, 363; People v. Blessett (2018) 22 Cal.App.5th

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903, 944–945, disapproved on another ground in Perez, supra, 9
Cal.5th at p. 14; People v. Vega-Robles (2017) 9 Cal.App.5th 382,
410–411; People v. Meraz (2016) 6 Cal.App.5th 1162, 1174–
1175.) Those cases pointed to language in Sanchez that
describes case-specific facts as those “relating to the particular
events and participants alleged to have been involved in the case
being tried.” (Sanchez, supra, 63 Cal.4th at p. 676.) They went
on to conclude that testimony about predicate offenses merely
conveyed “historical facts” about the gang’s conduct and
activities, as opposed to specific facts relating to the events and
participants involved in the case being tried. (Blessett, at p.
944.) Bermudez opined that “so long as the predicate offenses
do not involve defendant or individuals involved in the
defendant’s case[,] [s]uch predicate offenses are chapters in a
gang’s biography . . . not case-specific information.” (Bermudez,
at. p. 363.)
To determine whether predicate offenses are case-specific
or background facts, we must look beyond an isolated phrase in
Sanchez and instead probe the underlying rationale permitting
experts to rely on and relate certain hearsay. As Sanchez
observed, “expert witnesses are given greater latitude” to testify
regarding background information beyond matters within their
personal knowledge because their testimony may “provide
specialized context the jury will need to resolve an issue.”
(Sanchez, supra, 63 Cal.4th at p. 675.) Thus, experts are given
latitude over lay witnesses only to the extent they are conveying
acquired expertise in their field. Sanchez explained that “[o]ur
decision does not call into question the propriety of an expert’s
testimony concerning background information regarding his
knowledge and expertise and premises generally accepted in his
field. Indeed, an expert’s background knowledge and experience

16
 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

is what distinguishes him from a lay witness, and, as noted,
testimony relating such background information has never been
subject to exclusion as hearsay, even though offered for its truth.
Thus, our decision does not affect the traditional latitude
granted to experts to describe background information and
knowledge in the area of his expertise, even when based on
hearsay. Our conclusion restores the traditional distinction
between an expert’s testimony regarding background
information and case-specific facts.” (Id. at p. 685, italics
added.)
Sanchez and Veamatahau make clear that experts are
given greater latitude to testify about matter beyond their
personal knowledge because they are allowed to give an opinion
on subjects “sufficiently beyond common experience that the
opinion of an expert would assist the trier of fact” (Evid. Code,
§ 801, subd. (a)), so long as the opinion is based on matter “that
is of a type that reasonably may be relied upon by an expert in
forming an opinion upon the subject” (Evid. Code, § 801, subd.
(b)). “This latitude is a matter of practicality. A physician is not
required to personally replicate all medical experiments dating
back to the time of Galen in order to relate generally accepted
medical knowledge that will assist the jury in deciding the case
at hand. An expert’s testimony as to information generally
accepted in the expert’s area, or supported by his own [personal]
experience, may usually be admitted to provide specialized
context the jury will need to resolve an issue.” (Sanchez, supra,
63 Cal.4th at p. 675.) Hallmarks of background facts are that
they are generally accepted by experts in their field of expertise,
and that they will usually be applicable to all similar cases.
Permitting experts to relate background hearsay information is
analytically based on the safeguard of reliability. A level of

17
 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

reliability is provided when an expert lays foundation as to facts
grounded in his or her expertise and generally accepted in that
field. In Veamatahau, for example, the hearsay database
information was accepted by experts in the field as accurately
stating that pills of a certain appearance contain alprazolam.
(See Veamatahau, supra, 9 Cal.5th at p. 32.)
Conversely, if experts give testimony that goes beyond
their own experience or beyond principles generally accepted in
their field, the justifications for allowing greater evidentiary
latitude cease to apply. One commentator has noted that the
pre-Sanchez “not in for the truth” approach blurred the line
between general background knowledge and case-specific fact.
The previous approach “opened the door to abuse; namely,
expert witnesses being used as conduits to transmit
inadmissible hearsay that does not otherwise fall under a
statutory exception as assertions of fact to the jury. With such
a liberal approach to admissibility, there is a risk that damaging
inadmissible evidence, which would be unable to make its way
to the jury through the proper channels, could be smuggled to
the jury through the expert; or worse, parties may offer expert
testimony simply to place such damaging evidence before the
fact-finder disguised as expert basis testimony. The Sanchez
rule curbs this potential for abuse with its bright-line rule
prohibiting an expert from relating all case-specific hearsay
statements forming the basis of the expert’s opinion, unless such
hearsay statements fall under an applicable hearsay exception
or are properly admitted independent of the expert’s testimony.”
(Hamilton, The End of Smuggling Hearsay: How People v.
Sanchez Redefined the Scope of Expert Basis Testimony in
California and Beyond (2018) 21 Chap. L.Rev. 509, 511, fns.
omitted.) In other words, case-specific facts are not purged of

18
 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

their hearsay character just because an expert, rather than a
lay witness, is asked to repeat them in court.
The challenge, then, in Sanchez and Veamatahau was to
accommodate the longstanding rule allowing experts to testify
about “information generally accepted in the expert’s area” or
matters “in his field of expertise” (Sanchez, supra, 63 Cal.4th at
pp. 675, 676), yet restore the rule that experts may not simply
“regurgitate information from another source” (Veamatahau,
supra, 9 Cal.5th at p. 34). Sanchez and Veamatahau used the
terms “general background information” and “case-specific
facts” to distinguish, in the context of expert testimony, between
hearsay that may be admitted because it is generally accepted
by experts in the field, and facts that cannot be proven by
hearsay because that reliability justification is absent.15 These
latter case-specific facts must be proven through the testimony
of a witness with personal knowledge or by other admissible
evidence. (See generally Sanchez, supra, 63 Cal.4th at p. 677.)
The proper role of expert testimony is to help the jury
understand the significance of case-specific facts proven by
competent evidence, not to place before the jury otherwise
unsubstantiated assertions of fact. On the other hand, any

15
In this sense, the phrase “general background
information” from Sanchez (Sanchez, supra, 63 Cal.4th at p.
678) is tethered to the concept of information derived from
hearsay but generally considered accurate in a field of expertise.
As discussed ante (see p. 10, fn. 13), an expert’s personal
knowledge, on the other hand, may provide context relevant to
assist jurors in understanding the facts of a given case (Evid.
Code, § 801, subd. (a)), but it does not involve the recitation of
hearsay. As used in Sanchez the term “general background
information” refers to expert knowledge derived from hearsay
that is generally accepted as accurate by experts in the field.

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 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

witness, whether lay or expert, may testify to facts within their
personal knowledge, so long as those facts are relevant. The
reliability of those facts is furnished not by general agreement
among experts in their field, but by the witness’s personal
knowledge, for which there must be foundation. In addition, the
accuracy of that testimony can be tested by cross-examination
exploring the circumstances under which the witness’s
knowledge was acquired and whether it is being accurately
remembered and recounted. A lay witness need not know the
significance of the facts or how that significance might be
explained by an expert, but the witness must have the required
personal knowledge.
This conclusion mirrors the facts and analysis from
Veamatahau. There, hearsay information from the database
was properly admitted as background because it was generally
accepted in the field that the FDA markings were reliable
indications of the drug’s presence and also that the database
itself accurately connected the FDA marks with the presence of
that drug. (Evid. Code, § 801, subd. (b).)16 Based on those
hearsay background facts and his own personal observations
about the markings he saw, the expert formed an opinion to
which he testified, and on which the jury was entitled to rely, if

16
The initial burden is on the proponent to lay a foundation
of general acceptance. (Cf. Sargon Enterprises, Inc. v. University
of Southern California (2012) 55 Cal.4th 747, 769–773.) The
opposing party is, of course, entitled to challenge the foundation
by cross-examination or the introduction of contrary evidence.
The challenge may be brought in limine, renewed through a
motion to strike, or attacked as unreliable in argument to the
jury.

20
 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

they found it to be credible. (See Veamatahau, supra, 9 Cal.5th
at pp. 26–35.)
D. Predicate Offenses Are Case-specific and Must Be
Proven by Competent Evidence
The Attorney General argues that facts used to prove
predicate offenses are merely background information properly
supplied by expert testimony. This argument fails because of
the nature of the facts themselves, the absence of foundation
that they are generally accepted as reliable in a field of
expertise, and the allegations they are being offered to prove.
As Sanchez observed, general testimony about a gang’s
behavior, history, territory, and general operations is usually
admissible. (See Sanchez, supra, 63 Cal.4th at p. 698.) The
same is true of the gang’s name, symbols, and colors. All this
background information can be admitted through an expert’s
testimony, even if hearsay, if there is evidence that it is
considered reliable and accurate by experts on the gang.
Such information stands in contrast to information
regarding the commission of a particular offense on a specific
occasion. Experts with no personal knowledge of case-specific
facts, or who do not rely on other admissible evidence
establishing those facts, are simply “regurgitat[ing] information
from another source.” (Veamatahau, supra, 9 Cal.5th at p. 34.)
This is the practice rejected in Veamatahau and warned against
in Sanchez. “What an expert cannot do is relate as true case-
specific facts asserted in hearsay statements, unless they are
independently proven by competent evidence or are covered by
a hearsay exception.” (Sanchez, supra, 63 Cal.4th at p. 686; see
Veamatahau, at pp. 33–34.) Without independent admissible
evidence of the particulars of the predicate offenses, the expert’s
hearsay testimony cannot be used to supply them. In the

21
 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

absence of any additional foundation, the facts of an individual
case are not the kind of general information on which experts
can be said to agree.
The Attorney General relies on the Sanchez description of
case-specific facts as those relating to “the particular events and
participants alleged to have been involved in the case being
tried.” (Sanchez, supra, 63 Cal.4th at p. 676.) We acknowledge
that the statutorily required predicate offenses do not fit neatly
into the description Sanchez provided. At least some of these
offenses will most often have occurred before “the case being
tried” (ibid.) and will have been committed by others who were
not involved in the new charges at issue. But Sanchez was
addressing case-specific facts as they arose in the particular
matter at hand; it did not address the question we face here. For
reasons already explained, we conclude that facts concerning
particular events and participants alleged to have been involved
in predicate offenses, too, constitute case-specific facts that must
be proved by independently admissible evidence.
It should be recalled that the STEP Act sought a balance
between free association and protecting against the “clear and
present danger” posed by this defined kind of organized criminal
activity. (Pen. Code, § 186.21.) The statutory requirement that
predicate offenses be separately proven serves to maintain that
balance. Our interpretation here, requiring that this proof rest
on competent evidence, also furthers that legislative intent. In
this respect, the proof of predicate offenses is similar to other
kinds of case-specific facts that may have occurred before the
commission of the charged offenses. These kinds of facts include
evidence of motive, prior offense evidence admissible under
Evidence Code section 1101, subdivision (b), and prior
convictions suffered by the defendant on trial. It has long been

22
 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

recognized that these kinds of facts alleged in the current trial
must be proven by competent evidence.
In sum, the particular facts offered to prove predicate
offenses as required by the STEP Act are not the sort of
background hearsay information about which an expert may
testify. Competent evidence of those particulars is required.17
A gang expert may still render an opinion regarding the gang
membership of the perpetrator of a predicate offense in response
to a proper hypothetical question based on premises established
by competent evidence. (See Sanchez, supra, 63 Cal.4th at pp.
676–677.)
E. The Error Was Prejudicial
Here, Officer Calderon testified regarding the facts of
three predicate offenses of which he had no personal knowledge.
No independent proof of those facts was tendered by any witness
having personal knowledge. The People do not claim that any
hearsay exception would support their admission. We need not
address what exceptions might apply or what foundations would
be required to invoke them. On this record, Calderon’s
recitation of hearsay was inadmissible.
As to the standard for evaluating prejudice, Sanchez
observed that “improper admission of hearsay may constitute
state law statutory error” (Sanchez, supra, 63 Cal.4th at p. 698),
which would ordinarily be assessed under People v. Watson

17
We disapprove the following cases, which reached a
contrary conclusion: People v. Bermudez, supra, 45 Cal.App.5th
at page 363; People v. Meraz (2018) 30 Cal.App.5th 768, 781–
782; People v. Blessett, supra, 22 Cal.App.5th at pages 944–945;
People v. Vega-Robles, supra, 9 Cal.App.5th at pages 410–411;
People v. Meraz, supra, 6 Cal.App.5th at pages 1174–1175.

23
 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

(1956) 46 Cal.2d 818. That test inquires whether “it is
reasonably probable that a result more favorable to the
appealing party would have been reached in the absence of the
error.” (Id. at p. 836.) However, if the improperly admitted
hearsay is also testimonial within the meaning of the high
court’s confrontation clause jurisprudence (see, e.g., Crawford,
supra, 541 U.S. at pp. 68–69), the error is assessed under the
federal constitutional standard of Chapman v. California (1967)
386 U.S. 18, 24, which requires any error to be harmless beyond
a reasonable doubt. (See Sanchez, at p. 698.) The Attorney
General concedes that, on this record, the Chapman standard
applies here. As Sanchez notes, some of the contents of police
reports may be testimonial hearsay. (See Sanchez, at pp. 694–
695.)
The People argue any error was harmless beyond a
reasonable doubt because the gang membership of those
committing the predicate offenses was “supplied by admissible
expert testimony.” The People primarily point to the sequence
of Officer Calderon’s testimony, where he first described Arvina
13’s primary activities before giving detailed factual recitations
of the three predicate offenses. They argue Calderon could have
properly opined that the predicate offenses were committed by
gang members to benefit Arvina 13.
This argument is flawed. The People concede that, in
giving his opinion, Calderon related to the jury facts he gleaned
from inadmissible hearsay sources, including police reports,
about which he had no personal knowledge. 18 Calderon

18
Moreover, the Attorney General concedes that numerous
hearsay statements from police reports and field identification

24
 PEOPLE v. VALENCIA
Opinion of the Court by Corrigan, J.

considered this information as true and related it to the jury as
a reliable basis for his opinion. The jury was permitted to
improperly rely on that hearsay to conclude the predicate
offenses had been proven and that Valencia and Garcia acted
with intent to benefit the gang when they committed the crimes
with which they were charged. Based on the extent of the
evidence and the elements it was offered to prove, we cannot
conclude that the error was harmless under the Chapman
standard.19
III. DISPOSITION
The judgment of the Court of Appeal is affirmed.

CORRIGAN, J.

We Concur:
CANTIL-SAKAUYE, C. J.
LIU, J.
CUÉLLAR, J.
KRUGER, J.
GROBAN, J.
JENKINS, J.

cards were also improperly conveyed to bolster Calderon’s
opinion with respect to defendants’ own gang membership.
19
The People did not argue here or in the Court of Appeal
that the circumstances of the charged offenses could constitute
the necessary proof of predicate offenses. (See People v. Zermeno
(1999) 21 Cal.4th 927, 930–933; Loeun, supra, 17 Cal.4th at pp.
9–13.) We did not grant review to address such an assertion and
express no view on that question.

25
See next page for addresses and telephone numbers for counsel who
argued in Supreme Court.

Name of Opinion People v. Valencia and People v. Garcia
__________________________________________________________________

Procedural Posture (see XX below)
Original Appeal
Original Proceeding
Review Granted (published)
Review Granted (unpublished) XX NP opns. filed 7/10/18 – 5th Dist.
Rehearing Granted
__________________________________________________________________

Opinion No. S250218 and S250670
Date Filed: July 1, 2021
__________________________________________________________________

Court: Superior
County: Kern
Judge: Gary T. Friedman
__________________________________________________________________

Counsel:

Elizabeth J. Smutz, under appointment by the Supreme Court,
Michael B. McPartland, under appointment by the Court of Appeal,
for Defendant and Appellant Edgar Isidro Garcia.

Hilda Scheib, under appointment by the Supreme Court, for Defendant
and Appellant Jose Luis Valencia.

Mary K. McComb, State Public Defender, Hassan Gorguinpour,
Deputy State Public Defender, for Office of the State Public Defender
as Amicus Curiae on behalf of Defendants and Appellants.

Kamala D. Harris and Xavier Becerra, Attorneys General, Matthew
Rodriquez, Acting Attorney General, Gerald A. Engler and Lance E.
Winters, Chief Assistant Attorneys General, Michael P. Farrell,
Assistant Attorney General, Eric L. Christoffersen, Kathleen A.
McKenna, Rebecca Whitfield, Daniel B. Bernstein, Rachelle A.
Newcomb and Darren K. Indermill, Deputy Attorneys General, for
Plaintiff and Respondent in No. S250670.
Xavier Becerra, Attorney General, Matthew Rodriquez, Acting
Attorney General, Gerald A. Engler and Lance E. Winters, Chief
Assistant Attorneys General, Michael P. Farrell, Assistant Attorney
General, Louis M. Vasquez, Daniel B. Bernstein, Rachelle A.
Newcomb, Amanda D. Cary, Lewis A. Martinez and Darren K.
Indermill, Deputy Attorneys General, for Plaintiff and Respondent in
No. S250218.
Counsel who argued in Supreme Court (not intended for
publication with opinion):

Darren K. Indermill
Deputy Attorney General
1300 I St.
Sacramento, CA 95814
(916) 210-7689

Hilda Scheib
P.O. Box 29098
San Francisco, CA 94129
(415) 750-9397

Elizabeth J. Smutz
Central California Appellate Program
2150 River Plaza Dr., Suite 300
Sacramento, CA 95833
(916) 441-3792

Hassan Gorguinpour
Deputy State Public Defender
770 L St., Suite 1000
Sacramento, CA 95814-3362
(916) 322-2676