The 27-year-old man was pronounced dead at Centinela Hospital Medical Center early Thursday.
Sheriff's Lt. Holly Francisco said the man, whose name was not immediately released, had one wrist handcuffed to a gurney in a triage room with two deputies when he suddenly grabbed the gun from one officer's belt. She says another deputy fired a shot that killed him.
No one else was hurt.
The man had been arrested Wednesday for investigation of possessing a controlled substance.
While jailed at the South Los Angeles station, the man complained of feeling ill and was taken to the hospital.
