Petaluma police are investigating extensive gang graffiti in a westside city park and are asking for help from the public, said police officials.
They've arrested one suspected gang member, Jimy Soriano Vazquez, 19, of Petaluma. But two others were believed to be involved, said Sgt. Marty Frye.
Callers reported three people at McNear Park at about 12:50 a.m. Friday who were vandalizing structures.
An officer stopped Vazquez riding on a bike away from the G Street park.
Vazquez, who was on probation for vandalism and having a switch blade, was searched. Officers found he was carrying a switch blade again, as well as a small amount of marijuana, according to police reports.