Eighth Circuit: United States v. Terance Morice Highbull

Police officer's question "Do you have the phone" was insufficient to establish that the private citizen was an agent of law enforcement when she searched the vehicle for the phone, as the search was not requested, and the citizen had sufficient private motive to look for the phone.

http://media.ca8.uscourts.gov/opndir/18/07/172728P.pdf