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.

Officers determined the young man was involved in extensive park vandalism and arrested him on suspicion of felony vandalism, possessing the knife, probation violation and a gang enhancement, due to his gang connections, said Frye.

Vasquez was taken to the Sonoma County Jail and remained in custody on $40,000 bail.

In another recent graffiti case, a Petaluma officer spotted a young man vandalizing a new bus stop enclosure near East Washington Place shopping center, Frye said.

The suspect was seen early Saturday, writing on the structure with a permanent marker.

The man tried to run from the officer but was caught after he fell.

James Joseph Jensen, 18, of Rohnert Park was arrested on suspicion of felony vandalism, resisting arrest and committing a felony while out of jail on bail.

The damage from the graffiti was estimated at more than $1000, Frye said.

Jensen had previously been in custody involving an assault with a deadly weapon case. He was out of jail while awaiting possible prosecution on that case when he was arrested on the vandalism case, said Frye.

After Saturday's arrest Jensen was back in the Sonoma County Jail, but was released after posting bail, according to jail records.

Frye asked anyone with information about the park graffiti case to contact officers at (707) 778-4372 or call the anonymous tip line at (707) 781-1200 or email ppdtips@ci.petaluma.ca.us.