10th Cir. Dec. 7, 2009; US v. Pena-Montes, 08-2169

US v. Pena-Montes, 08-2169Suppression of passenger's detention was based on appearance of invalid license plate on vehicle; in fact plate was legal dealer plate and officer discovered this before questioning passenger, and no reasonable suspicion could be based on valid plate.  Detention of passenger was reversed and remanded as unreasonable seizure.  The scope of the initial traffic stop was exceeded once the officer reasonably knew there was no violation.

“As a general rule, once an officer’s purpose in a traffic stop based on probable cause or reasonable suspicion is complete, the officer must let the person go.” United States v. Ozbirn, 189 F.3d 1194, 1199 (10th Cir. 1999).