PETALUMA, Calif. (KRON) – An 18-year-old man was arrested for possession of a ghost gun on Friday, according to Petaluma Police Department.

Shortly before 2 p.m., staff at the Motel 6 on North McDowell Boulevard made entry into a room where the guest was supposed to have checked out. The staff made entry in order to clean the room.

The staff observed a handgun on the dresser and a large amount of marijuana in a backpack. The staff took both items and handed them over to police once they arrived.

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At around 6 p.m. staff alerted police that the suspect had returned to the hotel room and was upset about his missing items. Officers arrived on scene and arrested Valentin J. Rodriguez.

The gun recovered was determined to be a ghost gun and contained a 29-round high-capacity magazine. The magazine was loaded with .40 caliber piercing bullets.

Around 267 grams of marijuana were also recovered. The 18-year-old was charged with possession of a firearm without a serial number, possession of an assault weapon, possession of a large capacity magazine, and possession of armor piercing bullets.