People v. Hill, 123 N.E.3d 1236

Officer Baker observed a Chevrolet Monte Carlo rapidly decelerate near his squad car; the front-seat passenger was reclined low, partly hidden behind the B-pillar.
Based on the passenger’s hair, face, skin tone, and build, and Baker’s familiarity with a wanted person (Duane Lee), Baker followed the car about 30 blocks and requested backup before initiating a traffic stop to confirm identity.
On contact, Baker smelled "raw" cannabis and told occupants he thought the passenger was someone else; he then saw cannabis in plain view, removed and patted down the driver, and searched the vehicle, finding cannabis and a small rock testing positive for crack cocaine under the driver’s seat.
Defendant was charged with possession of less than 15 grams of cocaine; he moved to suppress the evidence arguing the stop lacked reasonable suspicion and the search lacked probable cause.
The trial court granted suppression, finding the officer was not certain the passenger was the wanted person and there was insufficient corroboration; the State appealed.
The appellate court reversed: it held the stop was justified by the officer’s reasonable, good-faith belief of mistaken identity (supported by the trial court’s finding of similarity) and the warrantless search was supported by probable cause once the officer smelled cannabis.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Validity of traffic stop	Officer reasonably suspected the passenger was a wanted person based on appearance and conduct; stop justified	Officer lacked certainty and corroborating facts; stop was unreasonable	Stop was reasonable; officer acted in good faith and need not be certain or have extra corroboration when suspecting a wanted person
Continuation of detention after ID uncertainty	Officer could reasonably continue detention to confirm identity and for officer safety	Once uncertainty established, detention should end	Continued stop was permissible given totality of circumstances (appearance, deceleration, seating posture, backup request)
Probable cause for vehicle search	Smell of raw cannabis and plain view observation provided probable cause under automobile exception	Decriminalization of small-quantity cannabis prevents smell alone from supporting probable cause	Probable cause existed; odor of cannabis (and plain view bud) justified warrantless search
Effect of decriminalization on smell-based probable cause	Smell still indicative of criminal activity because many marijuana-related acts remain unlawful; officers cannot measure quantity by smell	Decriminalization of small amounts negates automatic criminality from odor alone	Decriminalization does not eliminate the relevance of odor; smell can support probable cause

Terry v. Ohio, 392 U.S. 1 (establishes investigatory stop standard)
Hill v. California, 401 U.S. 797 (reasonable good-faith mistake of identity can justify seizure)
Heien v. North Carolina, 574 U.S. 54 (Fourth Amendment tolerates reasonable mistakes by officers)
Ornelas v. United States, 517 U.S. 690 (reasonable-suspicion and probable-cause determinations reviewed de novo, but factual findings given due weight)
Brinegar v. United States, 338 U.S. 160 (probable cause allows room for reasonable mistakes)
United States v. Arvizu, 534 U.S. 266 (reasonable suspicion is a commonsense, totality-of-the-circumstances inquiry)
People v. Stout, 106 Ill. 2d 77 (officer’s detection of odor of cannabis can establish probable cause)
Safunwa v. People, 299 Ill. App. 3d 707 (stops based on belief occupant matches wanted person may be reasonable)
Gordon v. People, 311 Ill. App. 3d 240 (reasonableness/good faith in mistaken-identity arrests)