SAN PABLO, Calif. -

UPDATE:  California Highway Patrol deactivated the Amber Alert shortly after midnight, Tuesday.

Authorities say the three children were found safely with a suspect, believed to be their mother.

An Amber Alert has been issued in the search for three young children whose father was found fatally shot in his backyard in the San Francisco Bay area Monday morning.

The alert issued Monday night for 12-year-old Hugo Anguiano, 6-year-old Merari Anguiano and 2-year-old Jenh Anguiano says their mother, 35-year-old Alicia Ortez, is suspected of taking them.

Authorities believe they were taken at about 11:30 Sunday night from their home in San Pablo, where they live with their father. San Pablo police say they are not calling Ortez a suspect in the killing. They say she is a transient who may not have access to a car, so no vehicle information was released.

The children's father, Oscar Angiano, was found dead in the backyard of a home on 16th street in San Pablo with a gunshot wound. Authorities said witnesses heard some gunfire, but wasn't sure where it came from. 

The mother, Alicia Ortez, is the prime suspect in the abduction, but not the killing. The father had custody of the children, but police said they are doing background information to see what their relationship is like.

The formal Amber Alert was issued for the children and their mother on Monday evening, even though there is no vehicle description to go on. 

Amber Alert Suspect