SAN DIEGO -- A statewide Amber Alert has been issued for an 8-year-old boy and 16-year-old girl who authorities believe disappeared from their San Diego County home with the man suspected of killing their mother and setting his house on fire Sunday evening.

Siblings Hannah Anderson and Ethan Anderson remained missing Monday evening following a house fire Sunday that turned up the body of their 44-year-old mother, who authorities believe was murdered by 40-year-old James Lee DiMaggio inside his Boulevard home.

San Diego County authorities responded to the home in the 2000 block of Ross Avenue about 8 p.m. and discovered the home and detached garage engulfed in flames, Lt. Glenn Giannantonio said. While extinguishing the blaze, crews discovered the body of Christina Anderson, the mother of the missing children, along with a slain dog.

Minutes later, crews uncovered the body of a child in the charred remains of the home's garage, Giannantonio said. The child has not been identified, and authorities would not say whether the child's body may be that of either Hannah or Ethan Anderson.

While DiMaggio and Christina Anderson were not dating, officials said, the two were in a "close, platonic relationship," and the man is known to both of her children. Authorities believe DiMaggio may be traveling to either Canada or Texas, and issued a statewide alert to reflect this possibility.

DiMaggio is thought to be traveling with one or both children in a blue Nissan Versa, California license plate 6WCU986.

Hannah is described as a white female with blond hair and blue eyes, about 5 feet 7 inches tall and weighing about 115 pounds. She has a belly button ring, nose stud and both of her ears pierced. Ethan is described is a white male, about 4 feet 11 inches tall and 65 pounds.

Anyone with information about the whereabouts of Hannah Anderson, Ethan Anderson or James Lee DiMaggio is asked to contact the San Diego County Sheriff's Office at 858-565-5200.

Contact Erin Ivie at eivie@bayareanewsgroup.com. Follow her at Twitter.com/erin_ivie.