SAN FRANCISCO (CBS SF) — A 19-year-old man has been arrested for alleged pimping and human trafficking after a traffic stop in San Rafael by an officer who became concerned about a teen girl riding in the car with three other males.

San Rafael police said an officer stopped a silver Mercedes driving through a motel parking lot on the 700 block of East Francisco Blvd. last Friday which had no front license plate.

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Cpl. Lilah Gavlick pulled over the vehicle in the area of Bellam Blvd. and the eastbound Interstate 580 on-ramp and saw that it was occupied by three males and one female.

The department says Gavlick is a recognized expert in human trafficking and often represents the city of San Rafael in community discussions on the subject. Gavlick saw the female passed out in the back seat of the Mercedes and initially unresponsive, with a short dress on and no shoes on, which made Gavlick become concerned for her safety, police said.

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After the female became responsive again, Gavlick determined she was a 17-year-old Modesto resident. During the investigation, the driver of the vehicle – 19-year-old Jayvon Gunn – made statements leading Gavlick to believe he was possibly trafficking the girl, police said.

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Gunn was arrested and booked into Marin County Jail on suspicion of human trafficking and pimping. The two other men in the car were interviewed and released without charges.

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The 17-year-old victim was interviewed, given information about human trafficking and resources to contact, and released to a family member, police said.