Police in Pleasanton are searching for the owners of two bicycles believed to have been stolen by a serial bike thief who was arrested Wednesday. Undercover officers made contact with 30-year-old Pleasanton resident Zachary Royer after a victim reported his bike stolen and later saw it listed for sale by Royer on Craigslist, according to Pleasanton police. Royer was allegedly in possession of three other bikes believed to have been stolen, and investigators have yet to identify the owners of two of them. The bikes are described as a men’s 21-speed mountain bike and a men’s 1-speed mountain bike. Anyone who had a similar bike stolen can call Pleasanton police Detective Michael Rossillon at (925) 931-5100. Royer, who has been convicted in another county for possessing and selling stolen bikes under similar circumstances, was arrested and booked at Santa Rita Jail. Police are reminding bike owners to register with the City of Pleasanton for easier identification in the event a bicycle is stolen and found.