A man was found shot to death in San Pablo Monday morning, and his three children and their mother are nowhere to be found, police said.
Police later issued an Amber Alert for the missing children shortly after 8 p.m. Monday.
Officers responded about 7:55 a.m. to reports of a man found dead from a gunshot wound in the backyard of a home in the 1600 block of 16th Street, according to San Pablo police.
Officers found the man, who was pronounced dead at the scene and whose name has not been released.
Police said a preliminary investigation indicates that the victim's three children, who live with him, as well as their mother, who doesn't live at the home, have not been located.
Police are asking for the public's help in finding the mother, identified as 35-year-old Alicia Ortez from the San Pablo-Richmond area, and her children, 12-year-old Hugo Anguiano, 6-year-old Merari Anguiano and 3-year-old Jenh Carlos Anguiano.
Ortez, who is the non-custodial, biological mother of the kids, is suspected of abducting the children at 11:30 p.m. Sunday, according to the issued Amber Alert. She is described as a Hispanic woman, standing 5 feet 5 inches tall, 160 pounds, black hair and brown eyes.
Police have not said if Ortez is a suspect in the man's death and said investigators have not determined a motive for the killing.
Anyone with information about the case is asked to call San Pablo police at 510-215-3150 or the West Contra Costa Crime Stoppers Tip Line at 510-799-8255.
NBC Bay Area's Jean Elle and Bay City News Service contributed to this report.