United States v. David Callison, 2 F.4th 1128

At night Officer Kilgore followed a car with a broken license-plate light, boxed it in after it pulled into a residential driveway, and confirmed the plate light was not working (Iowa Code §321.388).
Occupants: Rios (driver), Shannon (front passenger), Callison (rear passenger). Kilgore requested license/registration/insurance; Rios had a valid license and registration but could not immediately produce proof of insurance.
About five minutes into the stop Kilgore began asking travel-related questions while Rios continued searching for insurance; inconsistent answers emerged about why they were stopped and whom they were dropping off.
Around six minutes in Kilgore asked whether there was anything illegal in the car; he called for backup, ordered occupants out, and Shannon dropped a cigarette pack containing methamphetamine. A vehicle search and later a home search produced additional drugs and paraphernalia.
Callison moved to suppress vehicle and subsequent-home evidence as fruit of an unlawful extension of the traffic stop; the district court granted suppression. The government appealed. The Eighth Circuit reversed, vacating the suppression order and remanding.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether officer unlawfully extended the stop when he began asking travel-related questions ~5 minutes in	Callison: questions converted the stop into an investigative detention requiring reasonable suspicion; extension occurred ~5 minutes in	Government: Rios was still searching for insurance, so the officer was still handling the traffic matter and did not extend the stop	The court: no unlawful extension; initial travel questions occurred while officer was still "handling the matter" (insurance/ticketing)
Whether officer had reasonable suspicion to prolong the stop ~6 minutes in (when asked about illegal items)	Callison: officers lacked specific, articulable facts to suspect other criminality; continued detention unconstitutional	Government: facts (nighttime driveway stop, nervousness/avoidance, no known address, inconsistent answers) supplied reasonable suspicion	The court: reasonable suspicion existed by ~6 minutes; extension lawful
Whether suppression of drug evidence was warranted as fruit of unlawful seizure	Callison: evidence derived from an unconstitutional extension, so suppression required	Government: search and seizure followed a lawful extension based on reasonable suspicion; evidence admissible	The court: vacated suppression order and remanded for further proceedings consistent with its holdings

Rodriguez v. United States, 575 U.S. 348 (2015) (traffic stop cannot be prolonged beyond time to handle mission without reasonable suspicion)
Illinois v. Caballes, 543 U.S. 405 (2005) (dog sniff during lawful stop does not violate Fourth Amendment if it does not extend the stop)
Terry v. Ohio, 392 U.S. 1 (1968) (reasonable suspicion standard for brief investigative stops)
Illinois v. Wardlow, 528 U.S. 119 (2000) (reasonable-suspicion framework in stop-and-frisk context)
Reid v. Georgia, 448 U.S. 438 (1980) (actions characteristic of many innocent travelers do not establish reasonable suspicion)
United States v. Jones, 275 F.3d 673 (8th Cir. 2001) (any traffic violation supplies probable cause to stop)
United States v. Murillo-Salgado, 854 F.3d 407 (8th Cir. 2017) (indirect/incomplete answers can contribute to reasonable suspicion)
United States v. Walker, 555 F.3d 716 (8th Cir. 2009) (unusual driving behavior can support reasonable suspicion)
United States v. Hogan, 539 F.3d 916 (8th Cir. 2008) (nervousness and inconsistent answers can supply reasonable suspicion)
United States v. Foley, 206 F.3d 802 (8th Cir. 2000) (nervousness and inconsistent travel-related answers supported further inquiry)