A Petaluma man suspected of setting a former girlfriend's vehicle on fire was arrested Sunday, Petaluma police said.

Jonathan Gutierrez, 24, had been making harassing and threatening phone calls to the woman starting at about 10 p.m. Saturday, Sgt. Ken Savano said.

A neighbor called 911 at about 5:50 a.m. Sunday after hearing an explosion on Castle Drive and "saw a trail of gasoline on fire leading to the car that was fully engulfed," Savano said.

Gutierrez immediately became a prime suspect in the suspicious predawn fire, Savano said. The woman's car had been parked in front of a friend's house on Castle Drive. It was destroyed.

Officers found Gutierrez at about 6:15 a.m. downtown in his pickup, where they also found evidence from the fire, Savano said.

He was being held at the Sonoma County Jail in lieu of $250,000 bail on suspicion of felony arson.