It looked suspicious, a man using a flashlight to look into cars parked at a Home Depot lot at about midnight Monday, said Rohnert Park police.
Workers in the Redwood Drive area called police and officers arrived to find man they believed was looking for cars to burglarize, said Sgt. Eric Matzen.
Suspect Gonzalo Mejia, 25, was on probation for a felony drug conviction. He was arrested on suspicion of prowling and violating his probation.
Mejia was booked into the Sonoma County Jail.