SOUTH SAN FRANCISCO (CBS SF) — A Citrus Heights man was arrested for trafficking teenage girls in South San Francisco over the weekend, one day before local officials announced a special protocol to crack down on human trafficking in San Mateo County.

Michael Andrew Pierce, 24, was arrested Sunday after South San Francisco police conducted a prostitution sting operation at a hotel on East Grand Avenue.

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Officers who pretended to be clients made a date with an escort through, prostitution-based website that is frequently used for escort hook-ups in human trafficking cases in San Mateo County, police Sgt. Mike Neary said.

After setting up the meeting, the escort directed undercover officers to a room at the hotel, Neary said.

Officers found a 17-year-old girl and an 18-year-old woman in the room, along with evidence of a prostitution operation, Neary said.

Pierce, who was the registered guest of the room, was not on hotel grounds, but police detained him a short time later during a traffic stop as he was attempting to leave the area, police said.

According to a preliminary investigation, Pierce used social media websites to befriend teenage girls, police said. He was eventually able to convince them to work for him as prostitutes.

The 17-year-old girl who was contacted on Sunday was determined to be missing out of Santa Clara County. She had walked away from a youth shelter and was considered at risk as a sexually exploited minor, police said.

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Pierce was booked into San Mateo County Jail for human trafficking, pimping and pandering.

He remains in custody on $500,000 bail and is scheduled to be arraigned in San Mateo County Superior Court this afternoon.

On Monday, U.S. Rep. Jackie Speier joined law enforcement officials in South San Francisco to announce the implementation of the San Mateo County Human Trafficking Protocol, a set of guidelines and procedures that will help officers to detect and investigate human trafficking cases on the Peninsula.

The protocol also includes training for staff at local hotels to detect signs of human trafficking at their businesses.

Speier called human trafficking “modern day slavery” and said the new protocol will help rescue trafficking victims and more harshly punish traffickers.

Anyone who suspects a case of human trafficking in South San Francisco should notify the Police Department at (650) 877-8900. For suspected cases outside the area, concerned citizens can call the National Human Trafficking Hotline at (888) 373-7888.

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