State v. James Timothy Genous, 961 N.W.2d 41

At 3:36 a.m., Genous sat in a running car on a residential street; he turned off headlights briefly, a woman entered for ~10–15 seconds, then ran back into the house and the car left.
Officer Adam Stikl observed from an unmarked car; he had earlier received a department email identifying K.S. (a resident of that house) as a known heroin/narcotics user and reviewed her physical description.
Officer Stikl believed the woman matched K.S., knew the neighborhood had a reputation for drug activity, and—based on training—suspected a brief vehicle drug transaction.
Officer Stikl followed Genous for several blocks, stopped the vehicle, and officers discovered a handgun; Genous was charged as a felon in possession of a firearm.
The circuit court denied Genous’s suppression motion; the court of appeals reversed; the Wisconsin Supreme Court granted review.
The Supreme Court majority held the stop was supported by reasonable suspicion and reversed the court of appeals; a three-justice dissent argued the facts were too generalized and the “high-crime area” label was unsupported.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the traffic stop was supported by reasonable suspicion to investigate drug activity	Officer Stikl reasonably suspected a drug transaction based on: brief nighttime vehicle contact, headlights off then on, presence in a reputed drug area, and meeting with a known drug user	Facts were generic and not particularized to Genous: officer saw no exchange, identification of the woman was uncertain, and the "high-drug-trafficking area" claim was unsupported	Stop was lawful: under the totality of the circumstances a reasonable officer could suspect a drug transaction; suppression denied

State v. Young, 294 Wis. 2d 1 (2006) (discusses investigatory/Terry stops and reasonable-suspicion standard)
State v. Post, 301 Wis. 2d 1 (2007) (totality-of-the-circumstances review and deference to circuit-court factual findings)
Terry v. Ohio, 392 U.S. 1 (1968) (authorizing brief investigative stops)
United States v. Cortez, 449 U.S. 411 (1981) (totality-of-the-circumstances and officer inferences)
United States v. Sokolow, 490 U.S. 1 (1989) (aggregate of innocuous facts can amount to reasonable suspicion)
Illinois v. Wardlow, 528 U.S. 119 (2000) (role and limits of area reputation in reasonable-suspicion analysis)
State v. Waldner, 206 Wis. 2d 51 (1996) (Terry-stop principles in Wisconsin)