Christi Beth Perrin v. State, 06-14-00232-CR

Late-night patrol: Officer Brown observed a black sedan parked in a residential inlet with the driver’s door open and no one nearby around 12:30 a.m.; plate check showed the car wasn’t registered to the area.
Appellant Christi Beth Perrin appeared, entered the car, and drove toward the officer; Brown stopped her approximately 40 feet away.
On contact, Brown observed abnormal signs (shirt worn backwards, dilated pupils) and Perrin admitted taking Valium, Depakote, Adderall, and Trazodone earlier that day.
Brown administered standardized field sobriety tests: HGN showed no clues, but Perrin failed the walk-and-turn (5/8 clues) and one-legged-stand (3/4 clues); Brown arrested her for DWI.
A blood draw later revealed amphetamine, diazepam, nordiazepam (above therapeutic level), and valproic acid; a Drug Recognition Expert concluded impairment from combined CNS depressants and stimulants.
Procedural posture: State appeals/defends the trial court’s denial of Perrin’s motion to suppress; State argues officer had reasonable suspicion to detain under Terry and state law (Tex. Transp. Code §545.418).

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether officer had reasonable suspicion to detain Perrin	Perrin: stop was unlawful; officer lacked reasonable, articulable suspicion before stopping her	State: open unattended car at night, Perrin entering and driving away provided specific, articulable facts to justify a Terry stop (possible burglary/unauthorized use and traffic code violation)	Trial court properly denied suppression; detention reasonable at inception and scope
Whether stop could expand to DWI investigation	Perrin: initial stop unlawful so subsequent DWI inquiry tainted	State: after contact, officer developed reasonable suspicion of impairment based on observations and SFSTs, so scope lawfully expanded to DWI	Scope expansion to DWI was permissible

Terry v. Ohio, 392 U.S. 1 (1968) (establishes standards for investigative stops and scope of detention)
Whren v. United States, 517 U.S. 806 (1996) (objectively reasonable traffic stop standard irrespective of officer’s subjective intent)
Wade v. State, 422 S.W.3d 661 (Tex. Crim. App. 2013) (reasonable-suspicion inquiry under totality of circumstances)
Derichsweiler v. State, 348 S.W.3d 906 (Tex. Crim. App. 2011) (reasonableness can be satisfied by information suggesting crime is brewing; need not identify a specific offense)
Thomas v. State, 336 S.W.3d 703 (Tex. App.—Houston [1st Dist.] 2010) (open car door facing traffic can supply reasonable suspicion under Tex. Transp. Code §545.418)
State v. Kerwick, 393 S.W.3d 270 (Tex. Crim. App. 2013) (officer may briefly detain persons to establish identity and investigate suspected offenses)
Guzman v. State, 955 S.W.2d 85 (Tex. Crim. App. 1997) (standard of review deference to trial court fact findings on suppression)