Brentwood Police say the motive is unknown and it is an isolated incident.
One person was killed and three others injured in a shooting that sparked an altercation at a gym in Northern California, police said.
Brentwood Police told his ABC News that the three were injured and were taken to hospital on their own but survived.
Gunshots rang out just before 2 a.m. outside his 24 Hour Fitness in Brentwood, about 55 miles east of San Francisco.
This screen was taken from Google Maps Street View and is open 24 hours Fitness Gym
Google Maps Street View
Police said the "argument" began inside the gymnasium, on or near the basketball court, and "escalated" in the parking lot in front of the gymnasium.
At least he had two people pull out their guns and fire multiple shots, police said, citing surveillance video.
A man in his 20s, one of his four who were shot, died at the scene, according to police.
Police said the motive was unknown.
One suspect was detained, but police said no arrests had been made.
