A Los Angeles man charged with fatally shooting his 29-year-old son for being gay had repeatedly threatened to kill him over his sexual orientation, prosecutors say.

Amir Issa, 29, was found shot to death just outside the family home on Tuesday. While the Los Angeles County district attorney’s office charged father Shehada Issa, 69, on Friday with murder as a hate crime in the son’s death, investigators on Saturday still were trying to determine responsibility for a second killing at the home discovered by police at the same time, that of Amir’s mother, police spokesman Officer Mike Lopez said.

The mother, 68-year-old Rabihah Issa, had been stabbed repeatedly, coroner’s Lt. David Smith said.

Shehada Issa told police he shot his son Amir in self-defense after he discovered his wife’s body in their house.

Prosecutors gave a different motive for the son’s killing, however. ‘The murder was committed because of the victim’s sexual orientation and because of the defendant’s perception of that status and the victims’ association with a person and a group of that status,’ prosecutors said in a statement.

They did not elaborate. Police had no details Saturday on any of the alleged threats the father had made against his gay son.

Police arrested Issa at the scene Tuesday, after he made statements incriminating himself in the death of his son, Lopez said.

‘He claimed (the son) was armed with a knife, and there was no knife to be found. It was a horrible family tragedy,’ Detective John Doerbecker told the Los Angeles Daily News.

Authorities say the father used a shotgun to shoot his son in the abdomen and face, the Los Angeles Times reported.

A neighbor told the newspaper the young man had a troubled history and was involved in several incidents that led to police being called to the house. Francisco Gonzalez Jr. said the elder Issa once told him: ‘Drugs can mess up your life. My son had a great life, and then he did drugs and it all went away.’

Sgt. Greg Bruce told the Times the young man had been using the back of the house as an apartment, but his parents were seeking to sell the house and evict their son.

‘Our detectives were involved in the eviction process to try to get him removed from the property,’ he said. Bruce said he wasn’t aware of any disputes related to the son’s sexual orientation.

Issa is being held without bail pending his arraignment on 11 April. He faces up to life in prison if convicted of the charge.