San Francisco authorities have arrested a man suspected of robbing and committing a hate crime against an elderly Asian man over the weekend in a case that drew outrage from community members and politicians.

Dwayne Grayson, 20, was arrested on suspicion of robbery, elder abuse, probation violation for an earlier robbery and committing a hate crime, Police Chief Bill Scott said Thursday at a press conference in the Bayview neighborhood, where the attack occurred. Grayson was taken into custody in front of his home Thursday morning on the 100 block of Kirkwood Street in the Bayview.

Police said Grayson videoed the incident and posted it on social media, and they are seeking a second suspect, also a man, and expect to make an arrest soon.

please share this with your friends & family. this is so low, the older man was just trying to make ends meet for his family. he didn’t deserve this. this is ignorant, inhumane, & sickening. i’m praying for this man and his family. if you have any information, please reach out. pic.twitter.com/545xHFwPm4 — nikc (@nicholaaasli) February 24, 2020

A video depicting the attack went viral. It shows a man swinging what looks like a metal pole at an elderly Asian man, while a crowd gathered near Osceola Lane and La Salle Avenue mocks him. Police said the victim was robbed of recyclables he had collected.

“I hate Asians,” a person yelled.

Two security guards who, in a second video, appear to instruct the victim to leave the area after he was robbed, were placed on administrative leave by Critical Intervention Patrol.

The victim was “an elderly man doing what he can to support his family, being bullied and hurt in his own neighborhood,” Joyce Lam of the Chinese Progressive Association said at Thursday’s gathering.

The event was attended by Scott, Mayor London Breed, state Sen. Scott Wiener, state Assemblyman David Chiu, several members of the Board of Supervisors, and dozens of members of the community, both Asian and African American.

“I am tired of coming back to this place over and over because of violence,” Breed said, urging blacks and Asians to come together to resolve differences. “We’re better than that.”

“The way we stop senseless violence is by bringing communities together,” said Supervisor Shamann Walton, who represents the neighborhood as part of District 10. He said there had been a fatal shooting nearby on Friday that remains unsolved.

Bob Egelko is a San Francisco Chronicle staff writer. Email: begelko@sfchronicle.com Twitter: @BobEgelko