ORANGE, Calif. (AP) — A man awaiting trial in the 2016 killing of a Southern California mixed martial arts gym owner has died from injuries he received in a fight at an Orange County jail.

Kirk Price, 57, died Saturday, according to the Sheriff's Department.

Price was hurt in a Dec. 27 fight at the Theo Lacy Facility in Orange. The fight remains under investigation and other details weren't immediately released.

Price was awaiting trial for the March 2016 death of Fahness Lutalo, owner of OC Boxing MMA Academy.

Lutalo was shot several times at the Tustin gym. Price was arrested the next day.

Price and Lutalo had been friends for about a decade but acquaintances said Price had become increasingly jealous of Lutalo's success, the Orange County Register reported.

Price, who had two previous felony convictions, had pleaded not guilty to first-degree murder with an enhancement of being a felon in possession of a firearm, the paper reported.