An Amber Alert was in effect early Tuesday for the two missing children of a woman whose body was found inside a burned rural house near the U.S.-Mexico border, and authorities said the man suspected of killing the woman may have abducted the kids.

Authorities were trying to locate Hannah Anderson, 16, and Ethan Anderson, 8, whose mother, Christina Anderson, 44, was one of two people found dead by authorities sent to extinguish the fire Sunday night, a San Diego County sheriff's statement said.

A second body, that of a child, was found dead in the rubble of the house's detached garage, but the identity and manner of death remained undetermined. Authorities who released the news of the deaths Monday night wouldn't say whether the body may have belonged to one of Anderson's children.

A dog was also found dead inside the house.

The suspect, James Lee Dimaggio, 40, owned the home in Boulevard, some 60 miles southeast of San Diego, and lived there alone, the sheriff's statement said.

DiMaggio was in a "close platonic relationship" with Anderson, the sheriff's statement said without further explanation.

The Amber Alert said DiMaggio is believed to be driving a blue Nissan Versa with California license plates.