OAKLAND -- BART police are again asking the public to be aware of their surroundings and keep a close eye on their belongings after a cellphone robbery was caught on video.

The robbery occurred at 1:38 p.m. Tuesday on the platform at the Oakland 12th Street station. Trevel Thomas, 20, was arrested at Powell Street station in San Francisco less than an hour later, police said, and has since confessed to the crime.

In the videos, Thomas is seen sidling up to an unidentified rider as they wait for a train, then reaching down, grabbing the phone, and running up an escalator before leaping over the fare gate and fleeing the station.

"We encourage passengers to hold their belongings close to their bodies and make eye contact with those nearby," said BART police spokeswoman Era Jenkins. "Be extra cautious when standing near quick escape routes like escalators, stairs and train doors."

Contact Daniel M. Jimenez at djimenez@bayareanewsgroup.com. Follow him at Twitter.com/DMJreports.