Officials with the Baldwin Park Police Department said the shooting was reported just before 9:30 p.m. Sunday. Neighbors said they heard several gunshots ring out in the 4200 block of Merced Avenue, located near Los Angeles Street.
Yesli Velazquez Gonzalez, 23, of Baldwin Park died at the scene, the Los Angeles County coroner's office reported. Angel Velazquez died at a hospital, the coroner's office reported Wednesday.
Investigators said they believe the shooting was a domestic violence-related incident and that the gunman fled the scene.
On Monday, sheriff's Lt. Omar Camacho said the suspect being sought in the killings is Rigoberto Covarrubias, 36, who was the woman's boyfriend but not the boy's father. No arrest had been reported by the sheriff's department as of Tuesday morning.
Anyone with information on the case was asked to call homicide detectives at 323-890-5500 or Crime Stoppers at 800-222-TIPS (8477).
Are you or someone you know a recent survivor of domestic violence? Help is available. Los Angeles County has a hotline, which can be reached at 1-800-978-3600. A national hotline can be reached at 1-800-799-7233.
City News Service contributed to this report.