Two juveniles have been arrested for graffiti in downtown Petaluma. On Monday night, officers were dispatched to the Keller Street Parking Garage for vandalism in progress. Surveillance cameras from the parking garage and some other city facilities captured 4 subjects in the northwest stairwell who were graffitiing over previous graffiti on the walls. Police responded and detained the 4 subjects. Two of them had alcohol and marking pens in their possession and were also observed writing gang related graffiti. They were also wearing clothing that was associated with the graffiti. Both juveniles, ages 15 and 16, were arrested and transported to Juvenile Hall.