People v. Thomas, 2016 IL App (1st) 141040

On Sept. 15, 2009, two plain‑clothes Chicago officers were told in person by an unidentified man that a black male in a red shirt had placed a handgun into a backpack and was walking east on 80th Place; the informant declined to give his name.
Officers moved within seconds about a block‑and‑a‑half away, observed defendant (wearing a red shirt with a backpack) and approached for a field stop.
As an officer reached toward defendant, the backpack dropped to the porch, made a metallic “thud,” the officers opened it and found a loaded revolver and ammunition; defendant fled and was later arrested.
Defendant moved to quash arrest and suppress the gun as fruit of an unlawful Terry stop; the trial court denied suppression and convicted him after a bench trial of unlawful use/possession of a weapon by a felon.
After trial (but before appeal), Illinois Supreme Court decided People v. Aguilar invalidating the portion of the AUUW statute criminalizing carrying an uncased, loaded, immediately accessible handgun in public (void ab initio).
The appellate court reversed the denial of suppression, holding that post‑Aguilar the officers lacked reasonable suspicion (the tip only reported possession of a gun) and rejecting a good‑faith exception under Illinois void‑ab‑initio precedent.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the officers had reasonable, articulable suspicion to make a Terry stop based on the in‑person anonymous tip that defendant placed a gun in a backpack	Tip was sufficiently reliable: face‑to‑face informant risked anonymity, described basis of knowledge and predicted defendant’s direction, and officers corroborated appearance/location within seconds	Tip was unreliable and insufficient to justify a stop; officers failed to verify reliability before seizing defendant	Court: The tip was sufficiently reliable under pre‑Aguilar law, but post‑Aguilar the reported conduct (mere possession of a gun) is no longer criminal, so there is no reasonable suspicion today — stop was unlawful
Whether the exclusionary rule should be relaxed by a good‑faith exception because officers acted under a statute valid at the time	Evidence should be admissible under a good‑faith/ objective‑reliance rationale (U.S. cases like Leon/Krull)	Illinois precedent bars a good‑faith exception where the statute is void ab initio; admitting evidence would create an unconstitutional "grace period"	Court: Good‑faith exception declined under Illinois precedent (Carrera, Krueger); evidence suppressed as fruit of unlawful stop

Terry v. Ohio, 392 U.S. 1 (establishes reasonable‑suspicion standard for brief investigatory stops)
Florida v. J.L., 529 U.S. 266 (tip must be reliable as to illegal conduct, not only identity)
People v. Aguilar, 2013 IL 112116 (Illinois Supreme Court: statute banning carrying an uncased, loaded handgun in public unconstitutional; void ab initio)
People v. Carrera, 203 Ill. 2d 1 (Illinois Supreme Court rejects good‑faith exception where statute is void ab initio)
People v. Krueger, 175 Ill. 2d 60 (Illinois Supreme Court declined to apply federal good‑faith exception under state constitution)
Illinois v. Krull, 480 U.S. 340 (federal good‑faith rule for reliance on statute later invalidated)
United States v. Leon, 468 U.S. 897 (good‑faith exception to exclusionary rule)
Mapp v. Ohio, 367 U.S. 643 (exclusionary rule applies to states)