A caregiver reported hearing an argument between the two people, who were married, then heard gunshots. The caregiver then looked in the room and saw the man lying on the ground. The caregiver left and called police.
A weapon was recovered at the scene. The incident appeared to be a murder-suicide.
Sheriff's homicide detectives were investigating.
The senior-living community is located on Calle Aragon.
The couple owned their unit and had lived at the residence for approximately 11 years, according to Orange County Sheriff's Spokesman Jim Amormino. They were retired.
Authorities were trying to locate the couple's children, who live out of state.