concurring in part and dissenting in part.
I agree with the majority’s decision to affirm the district court’s denial of summary judgment on the knock-and-announce claim. Considering the evidence in the light most favorable to plaintiffs, the officers may not have waited a requisite amount of time before breaking down the Joneses’ door. Under Officer Wilhelm’s version of events, however, the time between the knock and announcement and the officers’ entry would have been sufficient to infer that plaintiffs had refused to allow the police to enter. Because there remains a substantial factual dispute about the critical issue of timing, I agree that plaintiffs should be permitted to go to trial on this claim.
I respectfully disagree, however, with the majority’s decision to grant summary judgment to plaintiffs on the warrant claim. While the police work in this case was not exemplary, I do not believe that Officer Wilhelm was on notice that his execution of the warrant was unlawful such that he should be stripped of qualified immunity. See Saucier v. Katz, 533 U.S. 194, 202, 121 S.Ct. 2151, 150 L.Ed.2d 272 (2001) (“The relevant, dispositive inquiry in determining whether a right is clearly es*470tablished is whether it would be clear to a reasonable officer that his conduct was unlawful in the situation he confronted.”) (emphasis added).
Although the warrant would not have told a reasonable officer unfamiliar with the building which apartment it referred to, Officer Wilhelm was aware of the layout of the building and the allegations of illegal drug activity on its second floor. From Wilhelm’s perspective, the warrant was not ambiguous. I cannot join, therefore, the majority’s conclusion that Wilhelm knew prior to entering the Joneses’ apartment that the warrant was invalid because it was open to more than one interpretation. Even though Wilhelm turned out to be mistaken in his belief that the warrant targeted plaintiffs’ apartment, in my judgment, this mistake was not so unreasonable as to strip him of qualified immunity. See Saucier, 533 U.S. at 202, 121 S.Ct. 2151 (quoting Malley v. Briggs, 475 U.S. 335, 341, 106 S.Ct. 1092, 89 L.Ed.2d 271 (1986) (“qualified immunity protects ‘all but the plainly incompetent or those who knowingly violate the law’ ”)); Anderson v. Creighton, 483 U.S. 635, 641, 107 S.Ct. 3034, 97 L.Ed.2d 523 (1987) (officer should not be stripped of qualified immunity where he conducted a search based on the erroneous belief that a bank robbery suspect was in plaintiffs home); Maryland v. Garrison, 480 U.S. 79, 87, 107 S.Ct. 1013, 94 L.Ed.2d 72 (1987) (“The [Supreme] Court has recognized the need to allow some latitude for honest mistakes that are made by officers in the dangerous and difficult process of making arrests and executing search warrants.”).
Wilhelm did not choose to search plaintiffs’ apartment at random or “maintain willful ignorance” of which apartment contained a methamphetamine lab. Rather, his belief that the warrant referred to the Joneses’ apartment was based on his own observations of traffic in and out of the building followed by activity in plaintiffs’ apartment. Wilhelm believed in good faith that the warrant referred to the Joneses’ apartment. Only after he entered that apartment did Wilhelm understand that the warrant was defective.
It is undisputed that, once an officer discovers a defect in the description of the place to be searched, he is obligated to cease the search if he cannot determine which precise location is the proper subject of the warrant. See Jacobs v. City of Chicago, 215 F.3d 758, 769 (7th Cir.2000). Wilhelm did just that. The facts of this case stand in marked contrast to those in Jacobs. In that case, the police officers had obtained a warrant to search a single-family residence. Id. at 763-64. When they arrived, the officers discovered that the address listed on the warrant was a multi-unit apartment building, which clearly should have alerted them that their search warrant was defective. Id. at 769. Despite there being “no indication that the officers were certain that plaintiffs’ apartment was the proper subject of the search,” the officers proceeded to search each of the apartments, entering the plaintiffs apartment only after they did not find what they were looking for in the first unit they chose to search. Id. at 771. This Court found that the execution of the search warrant was unreasonable, and that Supreme Court and Seventh Circuit precedent clearly established that a random search of apartments in a multi-unit building violates the Fourth Amendment. Id. The Court therefore held that the officers were not entitled to qualified immunity. Id. Unlike the officers in Jacobs, Officer Wilhelm did not conduct a “fishing expedition” or randomly search all the apartments in the building until he found the methamphetamine lab. Rather, he acted on his belief, albeit erroneous, that the warrant specifically targeted plaintiffs’ *471apartment. As soon as he realized he was in the wrong apartment, he did what he was required to do — immediately call off the search and exit the apartment.
Under these circumstances, it is my view that it would not have been clear to a reasonable officer in Wilhelm’s position that his entry into the Joneses’ apartment violated plaintiffs’ constitutional rights. I would hold that defendant was entitled to qualified immunity and affirm the district court’s entry of summary judgment in favor of defendant with respect to the warrant claim..