Kelly Thomas, 37, was rendered brain dead after a run-in with Fullerton police.
More than a dozen of Thomas' friends, family members and community members gathered outside the Fullerton Police Department's headquarters, saying they hope Thomas gets the justice he deserves.
Thomas' family members allege police used excessive force on Thomas.
Police say officers approached Thomas on the evening of July 5 after receiving reports that someone was breaking into cars near the bus depot in Fullerton. Police allege Thomas resisted arrest for several minutes.
"It was gang-involved, the way I see it, a gang of rogue officers who brutally beat my son to death," said Thomas' father Ron Thomas.
Police say they won't talk about what force was used since the incident is under investigation, but they say at least six officers were involved and two officers suffered broken bones in the fight.
Thomas' family says he was not a violent person.
"Very loving, very kind. He cared about family. I mean, his sister and brother in Nevada state, he would ask me constantly how they were," said Thomas' mother, Cathy Thomas.
Kelly Thomas' friends and family say they want answers from the Fullerton Police Department about what happened that night.
"I can't fathom that this happened. It's terrible. It makes me sick to my stomach, and I can't believe that they're not saying what happened," said his stepmother Dana Pape.
Kelly Thomas' father, who used to be a former Orange County Sheriff's Department deputy, said he feels betrayed, and added that he is embarrassed to ever have been affiliated with law enforcement.
"Can't even begin to explain the loss of a son. I just want to see him again. I want to hold him. It's just not fair," said Thomas' mother.
An official with the Fullerton Police Department said Chief Michael Sellers has been in contact with the victim's father.
The Fullerton Police Department told Eyewitness News that the incident was tragic and unfortunate. They also said they've invited the district attorney to investigate the case and the department is fully cooperating with the investigation.