Former Philadelphia police officer James Yeager, 26, who was fired after being caught on video in July assaulting a suspect, was arrested Thursday on charges of aggravated assault and related offenses, the District Attorney's Office said.

Yeager,  a four-year police veteran, was ordered fired in August after a cellphone video circulated online showing him critically injuring a handcuffed 21-year-old man at an on-the-street pool party in the Kensington section of the city. Yeager is seen lifting the man, Kevin Medina,  in the air and slamming his head into an aboveground swimming pool.

After Yeager's firing, the District Attorney's Office began seeking dismissal of charges against other people the officer had arrested. According to court records, five cases brought by Yeager have thus far been dismissed. All charges against Medina also have been dropped.

Ben Waxman, a spokesman for the District Attorney's Office, said that in addition to aggravated assault, Yeager has been charged with official oppression, possession of an instrument of crime, and simple assault.

The video of his actions, which has drawn more than 570,000 views, was taken and posted on Facebook by Ariel Rivera, 25, who at one time lived near the site of the beating. She did not respond to a request for comment.

John McNesby, leader for Philadelphia's chapter of the Fraternal Order of Police, said in a statement: "The viral video of this incident does not tell the entire story. Officer Yeager, like all citizens, is entitled to a fair hearing in the judicial system. And we look forward to officer Yeager being exonerated."