OPINION OF THE COURT
(March 16, 2007)
What is required for a finding of probable cause within the meaning of the Fourth Amendment can be a difficult question, made more difficult when, as here, there is a misunderstanding as to what one of our decisions has held. We write to correct that misunderstanding by making clear that state or local law does not dictate the reasonableness of an arrest for purposes of a Fourth Amendment probable cause analysis — a violation of state or local law is not, in other words, a per se violation of the Fourth Amendment. Rather, notwithstanding the validity of the arrest under state or local law, probable cause exists when the totality of the circumstances within an officer’s knowledge is sufficient to warrant a person of reasonable caution to conclude that the person being arrested has committed or is committing an offense. We find that the circumstances surrounding the warrantless arrest before us gave rise to probable *1014cause to believe that an offense had been committed and rendered that arrest reasonable under the Fourth Amendment. We will, therefore, reverse.
I.
In the early morning hours of Tuesday, August 17, 2004, sometime before 7:00 A.M., a boat carrying 32 illegal aliens ran aground on a reef in Christiansted harbor, St. Croix. An eyewitness on the wharf phoned the Virgin Islands Police Department (“VIPD”) to report that illegal aliens were exiting the boat and coming ashore.
Officer Aldemar Santos of the VIPD Marine Unit responded to the call between 7 and 8:00 A.M. From the wharf, he confirmed that a boat had indeed run aground in the harbor and that a number of people were still onboard. He also spoke with the citizen who had phoned the police, Mark Sperber, and Sperber pointed out four Hispanic-looking individuals sitting nearby on the boardwalk. Santos approached them and identified himself as a police officer. In response to his questioning, the individuals stated that they were Cubans, that they had come off the stranded boat, and that other aliens were in the vicinity.
Sperber independently advised Santos that other illegal aliens had come ashore and were around the corner. As additional police units arrived, Sperber offered to identify the other aliens. Santos, Sperber, and several uniformed officers walked down the boardwalk and around the corner, and Sperber pointed out three black males sitting on a bench. When the men saw the approaching officers, Santos later testified, “they stood up and started walking away really fast.” (App. vol. II at 39.)
Hoping to cut the men off, Santos walked down a side street while the other officers continued to follow the three men. On his radio, he heard an officer shout “he’s running” and another officer say that one of the men was heading toward a shopping area on Strand Street. Santos proceeded in the direction of the shopping area, where he saw appellant Kevin Laville, who he recognized as one of the men who had been sitting on the bench. Upon spotting Santos, Laville began to run, but stopped when Santos yelled “Police; stop.” Santos ordered Laville to put his hands up, patted him down, and placed him in handcuffs.
As they walked back to the police car, Laville stated, in response to Santos’s questions, that he was from Dominica and was a crew member on the stranded boat. Laville asked what island he was on, but Santos *1015believed that Laville knew he was on St. Croix. Meanwhile, the other officers apprehended all of the individuals who had come ashore. Later that morning, agents from Immigration and Customs Enforcement (“ICE”) came to the police station and took custody of all of the detained individuals, including Laville.
The next day, utilizing a photo array of all 32 individuals who had been on the boat, four of the Cuban passengers identified Laville and co-defendant Carter Magloire as the boat’s operators. That same day, ICE Agent David Levering and Officer Santos conducted a videotaped interview of Laville. After being advised of his Miranda rights, he again stated that he was from Dominica and had helped to operate the boat. He also said that he believed he had landed on the island of Tortola in the British Virgin Islands. Five additional passengers subsequently identified Laville as a member of the boat’s crew.
On September 14, 2004, a federal grand jury returned a three-count indictment charging Laville and Magloire with conspiracy to bring in illegal aliens in violation of 8 U.S.C. § 1324(a)(l)(A)(v)(i) (Count 1); bringing in illegal aliens for financial gain in violation of 8 U.S.C. § 1324(a)(2)(B)(ii) (Count 2); and bringing in illegal aliens in violation of 8 U.S.C. § 1324(a)(l)(A)(i) (Count 3). The District Court later severed Laville’s case from that of Magloire, and Magloire was tried and convicted on Counts 2 and 3.
Laville filed pro se motions to suppress the identifications and any evidence obtained as a result of his arrest, including statements made to Officer Santos and ICE. On August 16, 2005, the District Court held a suppression hearing at which Laville was represented by counsel. Officer Santos and ICE Agents Levering and Kirk Thomas testified to the circumstances of Laville’s arrest, his post-arrest statements, his identification by various passengers, and his ICE interview.
On February 2, 2006, the District Court granted Laville’s motion to suppress his post-arrest statements to the VIPD and ICE, but denied his motion to suppress the identifications. The government timely appealed.
II.
We have jurisdiction over this interlocutory appeal of a suppression order pursuant to 18 U.S.C. § 3731. In reviewing a suppression order, we exercise plenary review over the District Court’s legal conclusions, and *1016we review the underlying factual findings for clear error. United States v. Delfin-Colina, 464 F.3d 392, 395-96 (3d Cir. 2006).1
A. Laville’s Post-Arrest Statements to Officer Santos
The District Court found that Officer Santos arrested Laville without a warrant, and that at the time of the arrest probable cause to believe Laville was an alien smuggler was lacking. At most, the District Court found, there was probable cause to believe only that Laville had entered the United States illegally in violation of 8 U.S.C. § 1325 — a misdemeanor. Citing, but misreading, our decision in United States v. Myers, 308 F.3d 251 (3d Cir. 2002), the District Court concluded that because the validity of an arrest is determined by the law of the state where the arrest occurred, it need look no further than Virgin Islands statutory law to determine the reasonableness of Laville’s arrest under the Fourth Amendment. Under 5 V.I.C. § 3562(1), a misdemeanor must be committed in the presence of the officer in order to justify a warrantless arrest. Because the crime of illegal entry was completed before the officers arrived, the District Court reasoned, Santos had no authority under Virgin Islands law to conduct a warrantless arrest. Accordingly, there was a per se violation of the Fourth Amendment, and the Court suppressed Laville’s post-arrest statements.
Because the government, too, misreads Myers, it does not challenge the District Court’s conclusion that an arrest that is invalid under territorial law — or state or local law — is unreasonable per se under the Fourth Amendment. Instead, the government argues that Laville’s arrest was lawful because the crime of illegal entry had not been completed before the officers arrived or, alternatively, that illegal entry is a continuing offense. We need not address these arguments, however, because the reasonableness of Laville’s arrest under the Fourth Amendment does not depend on whether it was lawful under territorial law.
B. Our Holding in Myers
We are compelled, at the outset, to clarify what we did and did not hold in Myers. Myers concerned a police officer’s entry into an *1017apartment in response to a report of possible domestic violence involving a person with a gun, and the subsequent arrest of the defendant because of the officer’s suspicion that a crime was underway. We concluded that the officer was justified in entering the apartment but lacked probable cause to arrest the defendant once inside. Myers, 308 F.3d at 265. In reaching this conclusion, we painstakingly examined all of the circumstances within the officer’s know ledge at the time of the arrest. We did not consider these circumstances in isolation, but necessarily measured them against the potential offenses for which the defendant could conceivably have been charged. We found that the circumstances surrounding the arrest were insufficient to justify a reasonable belief that any offense had been committed. Id. at 284 (Alarcon, J., dissenting) (“The Majority has concluded that Officer Azzarano did not have probable cause to arrest Myers for any crime.”).
One of the state-law crimes we considered was the misdemeanor offense of simple assault. In discussing that offense, we noted a Pennsylvania statute authorizing warrantless arrests for misdemeanors only when they are committed in the presence of the arresting officer or when specifically authorized by statute. Noting that the validity of an arrest is determined by the law of the state where the arrest occurred, id. at 255, we concluded that the officer’s warrantless arrest for simple assault “is not authorized under Pennsylvania law unless the record establishes that a simple assault occurred in his presence.” Id. at 256 (emphasis added). It is important to note that we did not address the relationship between Pennsylvania law and the federal law of probable cause, and we certainly did not hold that the former dictated the latter. Indeed, we made it quite clear that the validity of an arrest under state law must never be confused or conflated with the Fourth Amendment concept of reasonableness, and that the validity of an arrest under state law is at most a factor that a court may consider in assessing the broader question of probable cause.2 Cf. Ker v. California, 374 U.S. 23, 38, 83 S. Ct. 1623, 10 L. Ed. 2d 726 (1963) (plurality opinion) (considering *1018whether arrest was reasonable under the Fourth Amendment “notwithstanding its legality under state law”). In conclusion, we held that the totality of the circumstances did not give rise to probable cause to believe that an assault had occurred at all, much less in the arresting officer’s presence. Myers, 308 F.3d at 258 (noting that the arresting officer’s testimony “does not establish a reasonable belief that Myers had assaulted Bennett, and it certainly does not establish any assault in the officer’s presence”); see also id. at 262 (“[T]he testimony does not support a finding that the officer had a reasonable belief that Myers had been involved in a physical altercation with Bennett. Likewise, the testimony does not corroborate that a ‘struggle occurred or that the officer thought one had.’”).
We did not hold in Myers and, indeed, have never held that an arrest that is unlawful under state or local law is unreasonable per se under the Fourth Amendment. Yet, the District Court effectively applied just such a per se rule when it held that Santos’s warrantless arrest for a misdemeanor that arguably did not occur in his presence violated 5 V.I.C. § 3562(1), the Virgin Islands’s misdemeanor-presence statute, and was, therefore, unreasonable under the Fourth Amendment.
A per se rule inappropriately draws federal courts into the enforcement of state and local law. By suppressing Laville’s post-arrest statements because it found a violation of the Virgin Islands’s misdemeanor-presence rule, the District Court was, in effect if not in fact, enforcing territorial criminal procedure, and doing so in a prosecution by the federal government for a violation of federal law. It is well understood, however, that “[m]ere violation of a state statute does not infringe the federal Constitution,” and that “[sjtate rather than federal courts are the appropriate institutions to enforce state rules.” Archie v. City of Racine, 847 F.2d 1211, 1216, 1217 (7th Cir. 1988) (en banc); see also Johnson v. Fankell, 520 U.S. 911, 919, 117 S. Ct. 1800, 138 L. Ed. 2d 108 (1997) (noting “‘the importance of state control of state judicial procedure’” (quoting Henry M. Hart, Jr., The Relations Between State and Federal Law, 54 COLUM. L. Rev. 489, 508 (1954))); Poulos v. State of New Hampshire, 345 U.S. 395, 409, 73 S. Ct. 760, 97 L. Ed. 1105 (1953) (stating, in the due process context, that “official failures to act in accordance with state law, redressable by state judicial procedures,” are not “state acts violative of the Federal Constitution”). A per se rule of *1019reasonableness would inappropriately enlist federal courts in the enforcement of state rules of criminal and judicial procedure.
Application of a per se rule could also lead to the creation of different standards governing arrests made by peace officers of different states for the same federal offense. Conceivably, fifty different constitutional standards of arrest, each one dictated by a respective state’s positive and decisional law, could result. What would be reasonable and constitutional in one state could be unreasonable and unconstitutional in another. Meanwhile, federal courts of appeals would be compelled to recognize— and, indeed, to perpetuate — such disparities among the states and territories within their jurisdictions. If, for instance, we were to uphold the District Court’s application of a per se rule here, we might nevertheless conclude, in some future case, that an otherwise identical arrest occurring in New Jersey is reasonable and constitutional. Such a patchwork of federal constitutional standards, arising as it were from the individual legislative enactments of the various states and territories, is inconsistent with our single federal constitution. See Martin v. Hunter’s Lessee, 14 U.S. (1 Wheat.) 304, 347-48, 4 L. Ed. 97 (1816) (noting “the importance, and even necessity of uniformity of decisions throughout the whole United States, upon all subjects within the purview of the constitution”).
Moreover, a per se rule could well create disparity in the constitutionality of arrests performed by state and federal officers for the same offense within the same state or territory. It is easy to imagine a scenario in which officers of the VIPD and officers of the ICE, working on a joint law-enforcement detail, simultaneously approach a group of suspected illegal aliens under circumstances similar to those presented here. Acting on what they believe to be probable cause, a VIPD officer and an ICE officer make simultaneous, warrantless arrests. If we were to apply a per se rule, we would likely be compelled to find that the arrest made by the VIPD officer was unreasonable per se and, therefore, unconstitutional, whereas the identical arrest made by the ICE officer was reasonable and constitutional. The Fourth Amendment does not permit, much less require, any such thing.
By engrafting territorial procedural requirements onto the federal constitutional standards governing seizure, the District Court went beyond simply determining the reasonableness of Laville’s arrest. Rather, the Court effectively required Santos to be certain that a *1020misdemeanor had been committed, by virtue of having witnessed its commission, and to ensure that conviction was possible. A significant body of caselaw makes clear why any such requirements simply cannot be, and why a Fourth Amendment determination cannot turn on the exigencies of the law of a particular state or territory or an officer’s knowledge of the elements of a particular offense and whether each element has been satisfied. “The test is one of federal law, neither enlarged by what one state may have countenanced nor diminished by what another may have colorably suppressed.” Elkins v. United States, 364 U.S. 206, 223-24, 80 S. Ct. 1437, 4 L. Ed. 2d 1669 (1960). As the Supreme Court emphasized in Draper v. United States, there is a “‘difference between what is required to prove guilt in a criminal case and what is required to show probable cause for arrest or search.’” 358 U.S. 307, 311-12, 79 S. Ct. 329, 3 L. Ed. 2d 327 (1959) (quoting Brinegar v. United States, 338 U.S. 160, 173, 69 S. Ct. 1302, 93 L. Ed. 1879 (1949)). And, as Judge Learned Hand recognized more than sixty years ago, the “‘reasonable cause’ necessary to support an arrest cannot demand the same strictness of proof as the accused’s guilt upon a trial, unless the powers of peace officers are to be so cut down that they cannot possibly perform their duties.” United States v. Heitner, 149 F.2d 105, 106 (2d Cir. 1945) (quoted in Draper, 358 U.S. at 312 n.4); see also Graham v. Connor, 490 U.S. 386, 396, 109 S. Ct. 1865, 104 L. Ed. 2d 443 (1989) (stating that in determining whether use of force violates the Fourth Amendment, “‘reasonableness’ ... must be judged from the perspective of a reasonable officer on the scene, rather than with the 20/20 vision of hindsight”).
And it is reasonableness that is the central inquiry under the Fourth Amendment. United States v. Williams, 417 F.3d 373, 376 (3d Cir. 2005). “[Sufficient probability, not certainty, is the touchstone of reasonableness under the Fourth Amendment.” Hill v. California, 401 U.S. 797, 804, 91 S. Ct. 1106, 28 L. Ed. 2d 484 (1971); see also Locke v. United States, 11 U.S. (7 Crunch) 339, 348, 3 L. Ed. 364 (1813) (recognizing that probable cause “means less than evidence which would justify condemnation”). Probable cause exists whenever reasonably trustworthy information or circumstances within an arresting officer’s knowledge are sufficient to warrant a person of reasonable caution to conclude that an offense has been or is being committed by the person being arrested. Draper, 358 U.S. at 313; Myers, 308 F.3d at 255.
*1021C. Laville’s Arrest Was Supported by Probable Cause
We must, therefore, determine whether Officer Santos’s warrant-less arrest satisfied the Fourth Amendment’s requirement that the arrest be reasonable. Reasonable suspicion and probable cause are determined with reference to the facts and circumstances within the officer’s knowledge at the time of the investigative stop or arrest. Devenpeck v. Alford, 543 U.S. 146, 152, 125 S. Ct. 588, 160 L. Ed. 2d 537 (2004); Florida v. J.L., 529 U.S. 266, 271, 120 S. Ct. 1375, 146 L. Ed. 2d 254 (2000). The arresting officer need not have contemplated the specific offense for which the defendant ultimately will be charged. The appropriate inquiry, rather, is whether the facts and circumstances within the officer’s knowledge at the time of an investigative stop or arrest objectively justify that action. Devenpeck, 543 U.S. at 153.
Santos went to the wharf between 7 and 8:00 A.M. to investigate a report, phoned in by Sperber, that a boat had run aground in Christiansted harbor and illegal aliens were coming ashore. When he arrived at the wharf, Santos observed firsthand that there was in fact a boat stranded in the harbor with a number of people still onboard. He also met face-to-face with Sperber, who pointed out a group of four individuals sitting nearby on the boardwalk. These individuals identified themselves to Santos as Cubans who “came into shore” off the boat (App. vol. II at 38), and, as the District Court found, “indicated that other aliens were in the vicinity” (App. vol. I at 6). Sperber separately informed Santos that more suspected aliens were “around the comer” and offered to point them out. (App. vol. II at 39.) Acting on this information, Santos and his fellow officers walked down the boardwalk and around the comer, and, there, found Laville and two companions sitting on a bench.
Taking these facts together with all reasonable inferences, see Terry v. Ohio, 392 U.S. 1, 27, 88 S. Ct. 1868, 20 L. Ed. 2d 889 (1968), we find that by the time Santos approached Laville and his companions on the boardwalk, he had, at the very least, reasonable suspicion to believe that criminal activity was afoot. If no further circumstances had existed, Santos would have been justified in performing an investigative stop of Laville and his companions. As it so happened, however, subsequent events elevated Santos’s reasonable suspicion to the level of probable cause for an arrest.
*1022When Laville and his companions spotted the approaching police officers, they immediately “stood up and started walking away really fast.” (App. vol. II at 39.) Their actions did not evidence an intent simply to go about their business, see Florida v. Royer, 460 U.S. 491, 497-98, 103 S. Ct. 1319, 75 L. Ed. 2d 229 (1983); rather, the men suddenly, and deliberately, fled. The rapid walking soon gave way to headlong flight: Santos heard a fellow officer exclaim of one of the suspects, “he’s running,” and personally observed Laville in open flight. (App. vol. I at 6-7.)
It is “well established that where police officers reasonably suspect that an individual may be engaged in criminal activity, and the individual deliberately takes flight when the officers attempt to stop and question him, the officers generally no longer have mere reasonable suspicion, but probable cause to arrest.” United States v. Sharpe, 470 U.S. 675, 705, 105 S. Ct. 1568, 84 L. Ed. 2d 605 (1985) (Brennan, J., dissenting); see also Peters v. New York, decided with Sibron v. New York, 392 U.S. 40, 66-67, 88 S. Ct. 1889, 20 L. Ed. 2d 917 (1968) (“[Deliberately furtive actions and flight at the approach of strangers or law officers are strong indicia of mens rea, and when coupled with specific knowledge on the part of the officer relating the suspect to the evidence of crime, they are proper factors to be considered in the decision to make an arrest.”); 2 WAYNE R. LAFAVE, SEARCH AND Seizure: A Treatise on the Fourth Amendment § 3.6 (4th ed. 2007) (“[I]f there already exists a significant degree of suspicion concerning a particular person ..., the flight of that individual upon the approach of the police may be taken into account and may well elevate the pre-existing suspicion up to the requisite Fourth Amendment level of probable cause.” (internal footnotes omitted)). “Headlong flight — wherever it occurs — is the consummate act of evasion: It is not necessarily indicative of wrongdoing, but it is certainly suggestive of such.” Illinois v. Wardlow, 528 U.S. 119, 124, 120 S. Ct. 673, 145 L. Ed. 2d 570 (2000). Thus, when Laville fled at the sight of the approaching officers, Santos no longer merely had reasonable suspicion to believe that criminal activity was afoot; he now had probable cause to make an arrest. We find that, given the totality of the circumstances, Santos’s arrest of Laville was reasonable and did not violate the Fourth Amendment.
*1023D. Laville’s Custodial Statement to ICE
Having erroneously found that Laville’s arrest was unlawful and that his statements to Santos must be suppressed, the District Court next considered the statement Laville made while in ICE custody. The District Court determined that a “new arrest” occurred when the VIPD transferred Laville into the custody of ICE. Finding that the government failed to make an independent showing of probable cause for this new arrest, the District Court ordered that Laville’s custodial statement to ICE also be suppressed.
If Laville’s arrest had been unreasonable under the Fourth Amendment, then the District Court may have been correct to suppress his custodial statement to ICE as fruit of the poisonous tree. See Wong Sun v. United States, 371 U.S. 471, 484-86, 83 S. Ct. 407, 9 L. Ed. 2d 441 (1963). We need not decide this question, however, because Laville’s arrest was reasonable. Where his initial arrest by territorial authorities did not violate the Fourth Amendment, ICE was not required to make an independent showing of probable cause before assuming custody. Such custodial transfers are relatively common in the immigration context, see, e.g., United States v. Bowley, 435 F.3d 426, 428 (3d Cir. 2006); Yang v. Maugans, 68 F.3d 1540, 1544 (3d Cir. 1995), and none of the authorities cited by the District Court, and none of which we are aware, even implies that a custodial transfer constitutes a “new arrest” requiring a separate showing of probable cause. See, e.g, California v. Hodari D., 499 U.S. 621, 624-28, 111 S. Ct. 1547, 113 L. Ed. 2d 690 (1991) (discussing when a Fourth Amendment “seizure” occurs, but not discussing a transfer of custody); Payton v. New York, 445 U.S. 573, 590, 100 S. Ct. 1371, 63 L. Ed. 2d 639 (1980) (involving warrantless entry of a home for purposes of making felony arrest); Sharrar v. Felsing, 128 F.3d 810, 819-20 (3d Cir. 1997) (same); United States v. Sanchez, 509 F.2d 886, 889 (6th Cir. 1975) (involving the Fourth Amendment’s particularity requirement for search warrants). We therefore find that Laville’s transfer into ICE custody was not a “new arrest” requiring an independent showing of probable cause, and that the District Court erred in suppressing Laville’s subsequent statement to ICE.
*1024III.
In determining whether an arrest is reasonable under the Fourth Amendment, courts must never lose sight of the fundamental principle that “‘reasonable suspicion’ and ‘probable cause’ ... are commonsense, nontechnical conceptions that deal with ‘the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.’” Ornelas v. United States, 517 U.S. 690, 695, 116 S. Ct. 1657, 134 L. Ed. 2d 911 (1996) (some internal quotation marks omitted) (quoting Illinois v. Gates, 462 U.S. 213, 231, 103 S. Ct. 2317, 76 L. Ed. 2d 527 (1983)); see also Sharrar, 128 F.3d at 818 (stating that courts must “use a ‘common sense’ approach to the issue of probable cause”). It is not consistent with this principle to determine the reasonableness of an arrest based solely upon the arresting officer’s technical compliance with state or local law.
Accordingly, we hold that the unlawfulness of an arrest under state or local law does not make the arrest unreasonable per se under the Fourth Amendment; at most, the unlawfulness is a factor for federal courts to consider in evaluating the totality of the circumstances surrounding the arrest. Because the District Court erroneously held that Officer Santos’s warrantless arrest was unreasonable per se and because it erroneously held that Laville’s transfer to ICE custody required a separate showing of probable cause, we will reverse the District Court’s order suppressing Laville’s post-arrest statements and remand for further proceedings consistent with this Opinion.
Laville has filed a pro se Rule 28(j) letter raising numerous constitutional objections to his prosecution and to United States immigration policy. As these are neither proper subjects for a Rule 28(j) letter nor proper matters for consideration on interlocutory appeal, we do not consider them.
Other courts of appeals are in accord. See, e.g., United States v. Mikulski, 317 F.3d 1228, 1232 (10th Cir. 2003); Pasiewicz v. Lalte County Forest Preserve Dist., 270 F.3d 520, 527 (7th Cir. 2001); United States v. Baker, 16 F.3d 854, 856 n.1 (8th Cir. 1994); cf. Atwater v. City of Lago Vista, 532 U.S. 318, 341-45, 121 S. Ct. 1536, 149 L. Ed. 2d 549 (2001) (considering state law as one measure of the reasonableness of warrantless arrests for misdemeanors).