The manhunt for an alleged murderer and kidnapper was expanded today after authorities received possible sightings of the suspect's vehicle in northern California and Oregon.
James Lee DiMaggio, 40, of Boulevard, Calif., is suspected of killing Christina Anderson, 44, and abducting one or both of her children, Hannah, 16, and Ethan, 8.
While an Amber Alert remains in effect for both children, authorities said it's possible a second body recovered from the scorched home where Anderson was found could belong to her son, Ethan.
"We're hopeful within the next day or so [we'll have confirmation], but there has been some difficulty," Capt. Duncan Fraser of the San Diego Sheriff's Department told ABCNews.com. "Because of the intense heat and the fire, it has become very problematic finding usable DNA on the body."
Until authorities have confirmation that the body is Ethan Anderson, Fraser said an Amber Alert will remain in effect for both children.
Fraser said the San Diego County Sheriff's Department has been in contact with their counterparts in Canada, since it is believed DiMaggio could try to cross the border. Authorities have also been working closely with Mexican authorities, he said, since San Diego County is located on the U.S.-Mexico border.
"At this point the suspect could be anywhere," Fraser said.
On Tuesday, the children's father, Brett Anderson, made no mention of his son when he issued an emotional plea to DiMaggio, asking that his daughter, Hannah, be let go.
"I'm begging you to let my daughter go. You've taken everything else," Anderson said at a news conference. "Hannah, we all love you very much. If you have a chance, you take it. You run. You'll be found."
DiMaggio and Christina Anderson "were in a close platonic relationship," according to the sheriff's department.
Angelina Amati, a family friend of the Andersons', told ABC News' affiliate KGTV that DiMaggio had a crush on Hannah Anderson.
"I honestly believe that Jim has snapped and couldn't handle the infatuation that he had with Hannah," she told KGTV.
The Anderson children were last seen about 5 p.m. Saturday, according to Fraser.
About 8 p.m. Sunday, fire officials were called to put out a blaze at DiMaggio's Boulevard, Calif., home and its detached garage.
Inside, they found Anderson's body, the body of what appeared to be a child and a dead dog, according to the sheriff's department.
DiMaggio was last seen driving a blue Nissan Versa with California license plates, is believed to be heading to either Texas or Canada, according to California Highway Patrol.
ABC News' Alexis Shaw contributed reporting.