ROWLAND HEIGHTS, Calif. — A man was arrested for fatally shooting his father on New Year’s Eve after he allegedly killed his son’s bedridden mother, girlfriend, and friend in Rowland Heights, California, according to the Los Angeles County Sheriff’s Department.

Police found two men, ages 54 (the father) and 27, and two women, ages 48 and 54, all suffering from gunshot wounds around 8:38 p.m. Thursday, KTLA reported. They were pronounced dead at the scene.

The 54-year-old father allegedly shot his son’s bedridden mother, girlfriend and friend, the Los Angeles Times reported. The motive behind the shooting is unknown at this time.

His 33-year-old son, identified as Christopher Morey by the LA Times, then wrestled his father to the ground and shot him once, killing him, police reported.

The son called the police after the shooting and was arrested for allegedly killing his father. He was held on $1 million bail.

Witnesses said to officials that only one of the victims was living at the house.

Officials did not release the identities of the other victims.

There is an ongoing investigation into the incident.