(dissenting). I write in dissent because I conclude that the majority opinion arrives at an erroneous result in its analysis of the search conducted by a probation supervisor (William Hammes) and a La Crosse probation agent (Michael Johnson): (1) due to its application of an incorrect standard of review to the decision of the circuit court, and (2) due to its assumption that even when there are reasonable grounds to conduct a probation search pursuant to Wis. Adm. Code § DOC 328.21(3), that constitutionally sufficient basis for the search is lost when a probation agent delays that search at the request of other law enforcement personnel who are also investigating the probationer.
Historic Fact/Constitutional Fact.
The majority's opinion turns on the standard of review it applies to the circuit court's decision. It concludes that whether Hammes and Johnson were stalking horses when they conducted the search is a question of historic fact. Based on that conclusion, it applies the "clearly erroneous" standard of review and affirms the circuit court. Whether the conclusion that Hammes and Johnson acted as stalking horses is a *713finding of historic fact or constitutional fact is an important question because Wisconsin appellate courts defer to findings of historic fact, while they review a circuit court's determinations of constitutional fact de novo. We independently review determinations of constitutional fact because it is our responsibility to uphold a consistent "scope of constitutional protections, representing the basic value commitments of our society, [which] cannot vary from trial court to trial court, or from jury to jury." State v. Fry, 131 Wis. 2d 153, 171, 388 N.W.2d 565, 573 (1986) (citations omitted).
No Wisconsin court has directly addressed whether the determination that probation agents were stalking horses for law enforcement is a question of historic fact or one of constitutional fact. The majority cites United States v. Harper, 928 F.2d 894 (9th Cir. 1991), United States v. Richardson, 849 F.2d 439 (9th Cir. 1988) and United States v. Jarrad, 754 F.2d 1451 (9th Cir. 1985), as the bases for its conclusion that the determination is one of historic fact. Although those cases do suggest that whether probation agents were stalking horses is a question of historic fact, none have any reasoning which led the courts to their conclusions. For example, in Jarrad, the earliest case, the issue is addressed solely by this statement: "This is a question of fact subject to the 'clearly erroneous' standard of review, even though the ultimate issue of whether the search conforms to the Fourth Amendment presents a mixed question of fact and law." Jarrad, 754 F.2d at 1454. The court engaged in no reasoning and no analysis prior to or subsequent to making that assertion.1 *714Richardson simply cites Jarrad, and no reasoning occurs in Harper. Rather, it appears from each case that the question of whether the determination of the lower court was one of historic fact or one of constitutional fact was never a contested issue. Here, the issue is contested.
In order to examine whether the conclusion of "stalking horse" is one of historic fact or constitutional fact, one must first define the terms "historic fact" and "constitutional fact" and then analyze how to tell the difference. Black's Law Dictionary defines a fact as, "[a] thing done ... an event... an actual occurrence." Black's Law Dictionary 591 (6th ed. 1990). This is the usual meaning of historic fact, i.e., it is something that has happened.
However, courts have long acknowledged that all facts are not historic facts. As Justice Frankfurter said: " ’[I]ssue of fact' is a coat of many colors. It does not cover a conclusion drawn from uncontroverted happenings, when that conclusion incorporates standards of conduct or criteria for judgment which in themselves are decisive of constitutional rights." Watts v. Indiana, 338 U.S. 49, 51 (1949). Additionally, learned treatises define a constitutional fact as something more than an event which happened. It is a fact whose "determination is 'decisive of constitutional rights.'" RUGGERO J. Aldisert, The Judicial Process 704 (1976) (quoting William R. Bishin & Christopher D. Stone, Constitutional Facts, Law, Language & Ethics 365-70 (1972)).2 Determinations of constitutional fact depend on find*715ings of historic fact. See Watts, 338 U.S. at 51-52.. Therefore, in analyzing into which category of fact the circuit court's "stalking horse" conclusion falls, we must determine whether it is an event or whether its determination is decisive of a constitutional right.
The circuit court's determination that the probation agents were "stalking horses" for law enforcement is a decision that it reached based upon events which had occurred between the probation agents and law enforcement officers. Similarly, the determinations of reasonableness, in regard to a search, and voluntariness, in regard to a confession, are also determinations which are made based on historic events in regard to the interaction between law enforcement personnel and a defendant. The supreme court has already concluded that the determinations of reasonableness and voluntariness are decisive of constitutional rights. See State v. Griffin, 131 Wis. 2d 41, 62, 388 N.W.2d 535, 543 (1986). In order to decide whether the determination that the agents acted as stalking horses was decisive of a constitutional right, we must examine under what circumstances such a determination may be made and what consequences flow therefrom.
Cooperation between law enforcement personnel and probation agents, in and of itself, will not convert an otherwise lawful probation search into an unconstitutional search. See Jarrad, 754 F.2d at 1454. It is only when probation agents are acting solely as instrumen-talities of law enforcement that they are stalking horses. See State v. Flakes, 140 Wis. 2d 411, 426-27, 410 N.W.2d 614, 620-21 (Ct. App. 1987).3, Therefore, *716when probation agents are stalking horses, they do not have reasonable grounds for a probation search, for if they had reasonable grounds, they could not be acting solely as a subterfuge for a criminal investigation.
The converse of that conclusion is also true. That is, if a probation agent had reasonable grounds to search, then he was not a stalking horse; rather, he would have acted within the scope of his own lawful authority. Therefore, I conclude that the determination that an agent has acted as a stalking horse also determines that a probationer has been subject to an unconstitutional search. Accordingly, that determination is a question of constitutional fact. Stated another way, the determination that probation agents acted as stalking horses precludes the conclusion that the search was a constitutionally permissible probation search.4 Based upon the foregoing, I conclude that the *717correct standard of review to apply to the determination of whether the agents were stalking horses is a de novo review.
Applying a de novo standard of review, I conclude that Hammes and Johnson had reasonable grounds to conduct the search. Reasonable grounds are determined by examining the standard expressed in WlS. Adm. Code § DOC 328.21(3)(a). See State v. Griffin, 131 Wis. 2d 41,61-62, 388 N.W.2d 535, 542-43 (1986), aff'd sub nom. Griffin v. Wisconsin, 483 U.S. 868 (1987). Under § DOC 328.2l(3)(a), a search of a probationer's living quarters may be conducted if "there are reasonable grounds to believe that the quarters . . . contain contraband." Contraband is "[a]ny item whose possession is forbidden by law." WlS. Adm. CODE § DOC 328.16(l)(b). Section 961.41(3g), Stats., provides that it is unlawful to possess a controlled substance, and cocaine is a controlled substance. See § 961.41(3g)(c).
The record reveals that Hajicek's probation officer received information on August 19, 1997 that Hajicek was deeply involved with cocaine and other drugs, as a user and as a source for others. According to DOC regulations, the agent contacted her supervisor, Hammes, and he decided to conduct a home search. Shortly after receiving Hajicek's file from the agent, Hammes learned that the Department of Narcotics Enforcement (DNE) was conducting an investigation of Hajicek as well. > He was asked by DNE if he would delay his search, in order to permit DNE to conclude its investigation. Hammes agreed to do so.
On September 24, 1997, the DNE agents informed Hammes that they had not gotten the information they had sought. Hammes testified that he then "went back to [his] initial decision to. conduct a search." No one asked Hammes to do the search, but he did ask for *718assistance from La Crosse County Sheriffs Department to secure the residence, as is usual and customary for searches conducted by probation officials. The sheriffs department informed Hammes that DNE agents were also available to assist with the search and Hammes decided to do it without further delay.
When they arrived at Hajicek's residence, Ham-mes and Johnson conducted the search. None of the DNE agents nor the sheriffs investigator participated in the search. Hammes located Percocet in Hajicek's bedroom. As soon as he found it, he advised Hajicek that he was on probation hold and he asked him to cooperate in the rest of the search. Hajicek then told Hammes that there was marijuana in a duffel bag in the garage. Hammes and Johnson found a large quantity of marijuana in a duffel bag in the garage and Hajicek was placed under arrest and removed from the residence.
The DNE agents did not seize any property as a result of the search that Hammes and Johnson conducted. Rather, they obtained a search warrant and came back to the residence and found significant amounts of drugs, $255,901 in cash and a variety of other drug paraphernalia, indicative of an ongoing drug selling venture. Based on those historic facts, which are uncontested in the record and the historic facts found by the circuit court which do not conflict with the facts related above, I would conclude that the probation agents were not stalking horses for law enforcement; that they had reasonable grounds to con- ‘ duct a probation search; and I would reverse the decision of the circuit court suppressing the evidence found.
*719Reasonable Grounds.
The majority opinion does not discuss whether Hammes had reasonable grounds to conduct a search of Hajicek's residence pursuant to Wis. Adm. Code § DOC 328.21(3). Rather, it seems to assume that if he did, he lost the constitutionally sufficient basis for the search because he acquiesced to a DNE officer's request to delay the search and did not conduct it until three weeks after he had initially decided to do so.5
As noted earlier in this dissent, I conclude that Hammes had reasonable grounds to conduct a constitutionally permissible search before he learned of DNE's investigation. There is no precedent for concluding that he lost those grounds when he delayed the search for three weeks. To the contrary, in State v. Axelson, 149 Wis. 2d 339, 441 N.W.2d 259 (Ct. App. 1989), we addressed whether an inventory search of an impounded vehicle remained constitutional if it was not conducted immediately upon impoundment, but delayed for a few days. We concluded that the search remained reasonable because there were valid reasons for doing the search at the time it was done. See id. at 343-44, 441 N.W.2d at 261.
A probation agent has an ongoing duty to supervise his or her clients during the terms of their probations. An agent does so to assure that the probationers are complying with the terms and conditions of their probation. See Flakes, 140 Wis. 2d at 428, 410 *720N.W.2d at 621. Therefore, if Hammes had information that Hajicek had contraband in his residence on the date he conducted the search, Wis. Adm. Code § DOC 328.16(l)(b) continued to provide a lawful basis for the search.
The record shows that at the time the probation search was conducted, Hammes had more, not less, information that Hajicek was involved with drugs because Hammes had verified some of the information in the tip the probation agent had received in August and he had the reports from DNE as well. Additionally, no one has identified a requirement that a probation search be conducted as soon as the agents have reasonable grounds to do so. Many times it may be more prudent to collect additional information before conducting a search. Therefore, I conclude that the reasonable grounds to search which Hammes had prior to agreeing to DNE's request to delay the search, were not lost and the search was constitutionally permissible when conducted three weeks later.6
Because I conclude that the search was reasonable, I conclude the court erred when it suppressed the evidence. Therefore, I must respectfully dissent.
United States v. Jarrad, 754 F.2d 1451, 1454 (9th Cir. 1985), cites Pullman-Standard v. Swint, 456 U.S. 273, 288 (1982), as precedent for its assertion. However, Pullman has *714nothing to do with the assertion made. Rather, it parses whether intent is a question of law or one of fact.
Examples of facts that have been set out as constitutional facts in Wisconsin are "voluntariness," as it relates to a confession or consent to search, and the "reasonableness" of a search. *715See, e.g., State v. Griffin, 131 Wis. 2d 41, 62, 388 N.W.2d 535, 543 (1986).
See also United States v. Harper, 928 F.2d 894, 897 (9th Cir. 1991) ("[Pjolice and parole officers are entitled to work *716together to achieve their objectives; concerted action does not in and of itself make a search constitutionally infirm."); United States v. Richardson, 849 F.2d 439, 441 (9th Cir. 1988) (" 'The fact that police investigation of [a crime] . . . preceded the involvement of parole officials does not in itself indicate that the search was initiated by police officers.'") (citations omitted).
The majority tries to avoid this constitutional connection by stating that it must determine if the search were a police search. The majority would characterize the search as a police search if Hammes and Johnson were stalking horses for law enforcement, rather than characterize it as a probation search without reasonable grounds. As a police search, it would then analyze whether any of the exceptions to a warrant exist. (Majority opinion at 706). However, the State has not argued that the search comported with a constitutional police search, as the majority notes in its brief paragraph holding the search unconstitutional. Furthermore, the stalking horse issue arises only when the constitutionality of a search conducted or authorized by probation officers is under review.
This issue was squarely presented by the State in its brief, but the respondent's brief does not address it. Rather, the respondent focuses on whether Wis. Adm. Code § DOC 328.22(1) required mandatory detention of Hajicek as soon as there were reasonable grounds to believe he was violating the conditions of his parole.
Even if the standard of review used by the majority opinion were correct, I would conclude that the finding that the probation agents were stalking horses was clearly erroneous because the record shows Hammes had a constitutionally permissible basis to search the residence; and therefore, the agents were not acting solely on behalf of other law enforcement. See State v. Flakes, 140 Wis. 2d 411, 426-27, 410 N.W.2d 614, 620-21 (Ct. App. 1987); Harper, 928 F.2d at 897.