An off-duty San Diego police officer shot and killed his brother during a violent incident Friday at the family's apartment in Chula Vista, police said.
The brother, who is mentally ill, had stabbed the officer several times as he "intervened to prevent his parents from being injured," Chula Vista police said.
When officers responded to an emergency call from the mother of the two men, they found one brother with gunshot wounds and the other in the parking lot bleeding from at least four stab wounds, police said.
Paramedics provided "immediate medical attention" to the brother who had been shot but he was pronounced dead at the scene. The other brother was taken to UC San Diego Medical Center, where he is listed in stable condition.
The two brothers lived with their parents in the apartment.
Chula Vista police are investigating and have been in contact with San Diego police. The names of those involved in the incident have not been released.