The Baldwin Park Police Department responded to a home in the 12700 block of Royston Street just before 5 a.m. Monday for a call about a suspicious person and a possible dead person at the location.
Investigators quickly identified 35-year-old Qihao Jin as the suspect and learned that his estranged wife's family was the target of the attack. Officers say he entered the home with a gun and shot the victims before fleeing the scene. His estranged wife was not home at the time.
His estranged wife's parents, 61-year-old Yulan Wang and 61-year-old Qiufu Jiang, were pronounced dead at the scene. Two adult males and one male juvenile at the home were not injured.
The 10-year-old girl was transported to a local hospital in critical condition where she later died.
Officers from the Anaheim Police Department found the suspect and his vehicle in the 100 block of Vermont Street in Anaheim on Nov. 17. Jin was pronounced dead at the scene from an apparent self-inflicted gunshot wound.
The relationship between the suspect and the 10-year-old girl was unclear.
Anyone with information about the incident is encouraged to contact the Los Angeles County Sheriff's Department's Homicide Bureau at (323) 890-5500.