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San Francisco police have arrested a 20-year-old man they say recorded a viral video of an elderly man collecting recyclables being taunted, attacked and robbed.

Dwayne Grayson was booked Thursday on suspicion of robbery, elder abuse, a probation violation for a prior robbery conviction and a hate crime enhancement, according to the San Francisco Police Department. He is being held without bond, custody records show.

The incident occurred about 5:30 p.m. Saturday in the Bayview neighborhood. A video, which went viral after being posted to social media, shows a man striking the victim, identified as a 68-year-old Asian man, in the head with a metal pole.

Authorities did not specifiy what role Grayson played, but they say he recorded the encounter and posted it to social media.

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