According to TMZ, Medina and his roommate Joshua Sutter had a fight which resulted in the latter's death.
After an argument, Sutter had apparently forced his way into Medina’s bedroom, where the actor's girlfriend was, and at some point Medina stabbed Joshua with a sword he kept by the door.
According to reports, Sutter was stabbed in the abdomen and found alive when emergency services arrived, but he later died in hospital.
'The victim and the suspect became involved in an argument, which turned into a physical altercation,' the Los Angeles County Sheriff's Department said.
'Suspect Medina retreated to his bedroom with his girlfriend but victim Sutter followed them and forced the door open.
'Suspect Medina stabbed victim Sutter once in the abdomen with a sword kept next to the bedroom door.'
The 37-year-old actor starred as the Red Power Ranger, in Power Rangers Wild Force. He has also had roles in ER, CSI: Miami, and Bad Blood.
He is due to appear in court on Tuesdsay, and his bail has been set at $1 million.