During an afternoon press conference Monday, authorities identified the suspect as 47-year-old Reginald Wallace. They said he was arrested at 4th Street and Western Avenue in Los Angeles.
He was being held at Los Angeles County jail without bail.
The shooting started with a fight Friday just before midnight.
Officers found multiple people with gunshot wounds inside the location. Three male victims were pronounced dead at the scene.
The coroner's office identified the deceased as Los Angeles residents Robert Earl Meekins Jr., 28, Astin Kyle Edwards, 28, and Michael Di'Shawn Radford, 20.
Torrance police Chief Eve Irvine said it was unclear if Wallace knew the victims. She said the three men were killed with a handgun that was not reloaded.
She said Wallace served 17 years in prison and was released in 2017 on parole for a previous conviction of assault with a deadly weapon with a firearm.