PETALUMA – Police in Petaluma arrested a man on probation Saturday night for illegal possession of a "ghost gun," authorities said. 

According to a release issued by the Petaluma Police Department Sunday morning, on Saturday evening at 8:46 p.m., an officer pulled over a vehicle for multiple code violations on the 700 block of East Washington Street.

The driver was identified as 46-year-old Petaluma resident Mark Offerman, who officers learned was on probation out of Sonoma County.  

A search of his vehicle revealed an unloaded handgun under the driver's seat.  A loaded magazine for the handgun was found near the center console. The unregistered handgun had no identifying marks, which is commonly referred to as a "ghost gun."  

Offerman was transported and booked at the Sonoma County Jail for concealed firearm in a vehicle and possession of an unregistered firearm. 

Offerman was arrested and booked at the Sonoma County Jail.