Can the police develop reasonable suspicion to make a traffic stop after the fact? When put that way, the obvious answer is no. If reasonable suspicion is required to make a traffic stop, one either has it at the time of the stop or doesn't.
But, to the courts, it wasn't such an obvious answer. At least before the Texas Court of Criminal Appeals issued its ruling in Martinez v. State, Nos. PD-1238-10 and PD-1239-10 (2011).
Police in Del Rio, Texas were notified by an anonymous caller that someone was acting suspicious and had put two bikes in the back of a blue pickup. Officer Hurley spotted a pickup that looked blue and began following it. After following the truck for four blocks, and not seeing any traffic violation, Officer Hurley stopped the truck.
When he walked up to the truck, the officer noticed two bikes in the bed. Upon contacting the Mr. Martinez, Officer Hurley noted a strong odor of alcohol and glassy eyes. To no one's surprise, Mr. Martinez was arrested for driving while intoxicated. To make matters worse, Officer Hurley also found a usable amount of marijuana after the DWI arrest.
Mr. Martinez filed a motion to suppress the stop, arguing that there was insufficient basis to stop his truck since the caller was never identified. He also argued that Officer Hurley lacked reasonable suspicion to make the stop. The trial court denied his motion and Mr. Martinez pled guilty to both charges. The Court of Appeals upheld the trial court's ruling.
The Court of Criminal Appeals then ruled that the officer lacked reasonable suspicion to make the stop. While the caller was never identified, she did appear at the scene following the traffic stop. However, the basis of the stop must be determined by the facts at the time of the stop, not by what the officer learns after making the stop. In this case, the officer had a tip from an anonymous caller. He never observed a traffic violation. He didn't find the bikes in the truck until after he made the stop. But for the illegal stop, he never would have noted any signs of intoxication; and, he never would have discovered marijuana in the truck but for the DWI arrest. In other words, in order to effect a traffic stop, the police must have specific articulable facts indicating that criminal activity is afoot before making the traffic stop. Any reasonable suspicion developed after the stop cannot be used to justify the stop in the first place.
The Court of Criminal Appeals reversed the conviction and remanded the case for further proceedings.