The black teenager who was slammed onto a car and punched by a white policeman during a video-taped arrest is suing the city of Inglewood, four of its officers, Los Angeles County and three sheriff's deputies.
The announcement comes as it emerged police in Oklahoma have launched an investigation into a similar incident of white officers using violence against a black suspect being video-taped.
The federal lawsuit filed by Donovan Jackson, 16, seeks unspecified damages and alleges misconduct and violations of constitutional rights.
The Inglewood Police Department and the Los Angeles County Sheriff's Department refused to comment.
Various law enforcement agencies have opened investigations into the arrest, and dozens of angry protesters descended on Inglewood City Hall demanding an end to police brutality and the sacking of Officer Jeremy Morse.
Mr Morse, a three-year veteran, has been suspended on paid leave.
The incident happened during a traffic stop on Saturday afternoon near the Los Angeles airport.
A tourist's video-tape showed Mr Morse hoisting a handcuffed Jackson to his feet, slamming his body onto a car, then punching him in the face.
Two other officers appear to intervene, with at least one trying to pull away the first officer's arm.
Police and sheriff's officials say the teenager lunged at deputies and was combative, while the boy's father, the driver of the car that was stopped, claimed his son co-operated and police attacked without being provoked.
The family's lawyer, Mr Joe Hopkins, says the teenager is developmentally disabled with no arrest record. The teenager was booked for investigation of assault on an officer; his father was cited for driving with a suspended license.
Police in Oklahoma City are now investigating new allegations that two officers used excessive force arresting a black man.
They were captured on an amateur videotape hitting an unarmed, 50-year-old man with their hands, knees and batons.
AP