Courts apply a two-part test in determining whether the emergency aid exception applies. Under the totality of the circumstances, a reasonable person would believe that: 1) there is an immediate need to provide aid or assistance to a person due to actual or threatened physical injury; and 2) immediate entry into an area in which a person has a reasonable expectation of privacy is necessary in order to provide that aid or assistance. State v. Ware, 2021 WI App 83, 400 Wis. 2d 118, 968 N.W.2d 752, 20-1559.

The results of a hospital blood test that were subpoenaed after the circuit court suppressed evidence from an unlawful blood draw were admissible under the independent source doctrine. The state’s decision to subpoena the hospital for the defendant’s medical records was not prompted by the deputy’s unlawful conduct because the state had reasonable grounds to suspect the defendant of operating while intoxicated prior to the deputy’s warrantless blood draw. The fact that the state subpoenaed those records only after the circuit court suppressed the deputy’s unlawful blood draw did not change the independent nature of the state’s suspicions that the defendant’s blood-alcohol concentration was over the legal limit. Furthermore, the evidence discovered through the state’s subpoena—the hospital’s diagnostic blood test—was untainted by the deputy’s unlawful conduct, thus suppressing it would not serve the exclusionary rule’s purpose. State v. Van Linn, 2022 WI 16, 401 Wis. 2d 1, 971 N.W.2d 478, 19-1317.

Police lack reasonable suspicion to justify an investigatory stop if there are not specific, articulable facts, and all rational inferences that may be drawn from those facts, to suspect that criminal activity is afoot. When a deputy observed an individual wearing black clothing and riding a bicycle, crossing and then leaving publicly-accessible school grounds in the early hours of a Sunday morning, while the state was under the Department of Health Services’ Safer at Home order due to the COVID-19 pandemic, the state failed to clear the “low bar” of reasonable suspicion and instead relied on what could be described, at most, as “a mere hunch” of the deputy. That is, the evidence regarding events leading up to the stop failed to establish articulable facts and rational inferences from those facts that could have led a reasonable officer to suspect that the defendant had engaged in criminal activity, was currently doing so, or was about to do so. State v. Meddaugh, 2022 WI App 12, 401 Wis. 2d 134, 972 N.W.2d 181, 21-0939.

Lacking a warrant or exigent circumstances, officers had no lawful basis to open the defendant’s hotel room door—even just the few inches they initially could—and peer inside or even speak to the defendant through that opening. Absent the officer’s unlawful opening of the defendant’s door and utilization of that opening, there was no reason to believe the defendant ever would have even gotten out of bed much less been in a position to visibly turn away from the officers at the door. Under the facts of this case, the officers’ forced entry into the room—leading to the discovery of the gun—cannot be legitimized by the defendant’s turning away from the door because the officer’s observation of that action was not lawfully grounded. State v. Bourgeois, 2022 WI App 18, 401 Wis. 2d 489, 973 N.W.2d 818, 20-1808.

In this case, the officers had reasonable suspicion to believe the defendant was involved in criminal activity when, in the course of responding within one minute after receiving a ShotSpotter report of gunfire in a residential neighborhood, the officers saw a single suspect near the scene make furtive movements suggesting concealment of a handgun. Looking at the whole picture, as the officers were required to do, they made a well-informed and reasonable inference that the defendant might be the shooter. State v. Nimmer, 2022 WI 47, 402 Wis. 2d 416, 975 N.W.2d 598, 20-0878.

The search-incident-to-arrest exception permits police to search items not actually located on the person but also in the area within the arrestee’s reach. The scope of a search incident to arrest is confined to the area from within which the suspect might gain possession of a weapon or destructible evidence. A search may precede an arrest so long as the officer had probable cause to arrest prior to the search. State v. Meisenhelder, 2022 WI App 37, 404 Wis. 2d 75, 978 N.W.2d 551, 21-0708.

A “knock and talk” investigation is not a search but instead is an investigative technique premised on the implicit license that a visitor, or neighbor, would have with regard to entering one’s constitutionally-protected curtilage. In limited scenarios, the implicit license may extend to an alternative approach to the house or back entryway depending on the facts of a case. However, in this case, the officers’ warrantless entry into the defendant’s fenced-in backyard was not a valid knock and talk investigation and therefore violated the 4th amendment. The backyard was surrounded by a tall, solid wooden fence, and, even though the gate to the backyard was open, it was blocked by a large garbage can. It is hard to believe that a private citizen in the alley would consider the fence, together with the garbage can impeding the opening in the fence, as an invitation to approach the side door of the unattached garage. State v. Wilson, 2022 WI 77, 404 Wis. 2d 623, 982 N.W.2d 67, 20-1014.

The 4th amendment requires a police officer to have particularized reasonable suspicion that a crime or non-criminal traffic violation took place before performing a traffic stop. Reasonable suspicion must be founded on concrete, particularized facts warranting suspicion of a specific individual, not inchoate and unparticularized suspicions or hunches. In this case, a stop based on the generic description of a Harley-Davidson motorcycle recently seen driving erratically in the area fell short of that threshold. State v. Richey, 2022 WI 106, 405 Wis. 2d 132, 983 N.W.2d 617, 21-0142.

In this case, the defendant, a detective with the county sheriff’s department, had a reasonable expectation of privacy in the contents of the defendant’s Dropbox account. Although it was established using the defendant’s county email address, the defendant paid to create the private account, the account was password protected and accessible through the defendant’s private devices, and the account was not stored on county property. In addition, although the defendant’s account was held by Dropbox, an independent entity, the defendant did not grant a third party access to the password or the account when the defendant used the account to share specific documents with third parties. Thus, law enforcement engaged in a search of the defendant’s account within the meaning of the 4th amendment. State v. Bowers, 2023 WI App 4, 405 Wis. 2d 716, 985 N.W.2d 123, 21-1767.

A Dropbox account is most reasonably comparable to a modern-day version of a container used to store personal documents and effects. It is well established that individuals generally have a reasonable expectation of privacy in locked or closed containers, which are comparable to password-protected Internet-based accounts. State v. Bowers, 2023 WI App 4, 405 Wis. 2d 716, 985 N.W.2d 123, 21-1767.

In this case, the officer seized the defendant at the defendant’s home under the 4th amendment when the officer denied the defendant’s request to terminate the encounter while standing in the doorway of the defendant’s home. There is no reasonable suspicion exception to the warrant requirement under the 4th amendment for a person’s seizure in the person’s home or curtilage. State v. Cundy, 2023 WI App 41, 409 Wis. 2d 34, 995 N.W.2d 266, 22-0540.

A canine sniff of the exterior of a vehicle is not a search within the 4th amendment. The occupant of a vehicle has no reasonable expectation of privacy in the air space surrounding a vehicle that the occupant is occupying in a public place. However, an individual has a property interest in the interior of a vehicle under the common-law trespassory test, and a canine entry into the vehicle constitutes a search within the meaning of the 4th amendment. State v. Campbell, 2024 WI App 17, 411 Wis. 2d 439, 5 N.W.3d 870, 20-1813.

Under the so called “instinct exception” to the 4th amendment’s warrant requirement, canine searches that naturally extend into a vehicle during a traffic stop are constitutional if the canine conducts the search “instinctively” and without an officer’s direction, assistance, or encouragement. Even if the instinct exception were to be recognized in this state, the exception did not apply to the canine’s searches in this case. The canine did not instinctively enter the defendant’s vehicle because the officer had full control of the canine and implicitly encouraged it to enter through the driver’s side door. State v. Campbell, 2024 WI App 17, 411 Wis. 2d 439, 5 N.W.3d 870, 20-1813.

A warrantless, non-exigent, felony arrest in public was constitutional despite the opportunity to obtain a warrant. United States v. Watson, 423 U.S. 411, 96 S. Ct. 820, 46 L. Ed. 2d 598 (1976).

When a driver was stopped because of expired license plates, a police order to get out of the car was reasonable and a subsequent “pat down” based on an observed bulge under the driver’s jacket resulted in the legal seizure of an unlicensed revolver. Pennsylvania v. Mimms, 434 U.S. 106, 98 S. Ct. 330, 54 L. Ed. 2d 331 (1977).

A burning building clearly presents an exigency rendering a warrantless entry reasonable, and fire officials need no warrant to remain in a building for a reasonable time to investigate the cause of the fire after it is extinguished. Michigan v. Tyler, 436 U.S. 499, 98 S. Ct. 1942, 56 L. Ed. 2d 486 (1978).

The warrantless installation of a pen register, that recorded telephone numbers called but not the contents of the calls, did not violate the 4th amendment. Smith v. Maryland, 442 U.S. 735, 99 S. Ct. 2577, 61 L. Ed. 2d 220 (1979).

A warrantless search of a suitcase in the trunk of a taxi was unconstitutional. Arkansas v. Sanders, 442 U.S. 753, 99 S. Ct. 2586, 61 L. Ed. 2d 235 (1979).

Police may not make a warrantless, nonconsensual entry into a suspect’s home in order to make a routine felony arrest. Payton v. New York, 445 U.S. 573, 100 S. Ct. 1371, 63 L. Ed. 2d 639 (1980).

That police had lawful possession of pornographic film boxes did not give them authority to search their contents. Walter v. United States, 447 U.S. 649, 100 S. Ct. 2395, 65 L. Ed. 2d 410 (1980).

An officer who accompanied an arrestee to the arrestee’s residence to obtain identification properly seized contraband in plain view. Washington v. Chrisman, 455 U.S. 1, 102 S. Ct. 812, 70 L. Ed. 2d 778 (1982).

Officers who have legitimately stopped an automobile and who have probable cause to believe contraband is concealed somewhere within it may conduct a warrantless search of the vehicle as thorough as could be authorized by warrant. United States v. Ross, 456 U.S. 798, 102 S. Ct. 2157, 72 L. Ed. 2d 572 (1982).

When an officer, after stopping a defendant’s car at a routine driver’s license checkpoint, saw a tied-off party balloon in plain sight, the officer had probable cause to believe the balloon contained an illicit substance. Hence, a warrantless seizure of the balloon was legal. Texas v. Brown, 460 U.S. 730, 103 S. Ct. 1535, 75 L. Ed. 2d 502 (1983).

A warrantless search by arson investigators of the defendant’s fire-damaged home that was not a continuation of an earlier search was unconstitutional. Michigan v. Clifford, 464 U.S. 287, 104 S. Ct. 641, 78 L. Ed. 2d 477 (1984).

When a damaged shipping package was examined by company employees who discovered white powder, a subsequent warrantless field test by police was constitutional. United States v. Jacobsen, 466 U.S. 109, 104 S. Ct. 1652, 80 L. Ed. 2d 85 (1984).

Discussing the “open fields” doctrine. Oliver v. United States, 466 U.S. 170, 104 S. Ct. 1735, 80 L. Ed. 2d 214 (1984).

The warrantless, nighttime entry of the defendant’s home for arrest for a civil, nonjailable traffic offense was not justified under the “hot pursuit” doctrine or the preservation of evidence doctrine. Welsh v. Wisconsin, 466 U.S. 740, 104 S. Ct. 2091, 80 L. Ed. 2d 732 (1984).

School officials need not obtain a warrant before searching a student. The legality of the search depends on the reasonableness, under all circumstances, of the search. New Jersey v. T.L.O., 469 U.S. 325, 105 S. Ct. 733, 83 L. Ed. 2d 720 (1985).

When officers were entitled to seize packages in a vehicle and could have searched them immediately without a warrant, a warrantless search of the packages three days later was reasonable. United States v. Johns, 469 U.S. 478, 105 S. Ct. 881, 83 L. Ed. 2d 890 (1985).