The victim, later identified as Steven Arredondo of Rancho Cucamonga, was discovered in the parking lot of the Montecito Apartments in the 11300 block of Mountain View Drive.
Deputies first showed up at the apartment after receiving a call about a man lying in the parking lot. When they arrived, they discovered that the man had been shot to death.
Detectives are still trying to uncover the motive behind the fatal shooting.
If you have any information about this case, you're urged to contact Detective Mike Flores with Homicide Detail at (909) 387-3589 or the We-Tip Hotline at (800) 78-CRIME.