The pair was apparently spotted camping near Cascade, Idaho, by a group of horseback riders Wednesday, a few miles from a road where the car that had been the subject of an Amber Alert was found hidden in some brush.
The riders told authorities the two campers appeared to be in good health and there was no obvious indication the young woman, believed to be Hannah Anderson, 16, was being held against her will.
"I am very confident and optimistic," San Diego County Sheriff Bill Gore said at a news conference. "She appeared to be in good health and was alive on Wednesday."
Gore said the riders were not aware of the Amber Alert for Anderson and suspect James DiMaggio when they came across the pair during a ride in the Frank Church River of No Return Wilderness. They did not learn about the massive manhunt for the pair until Thursday and alerted authorities too late in the day for Ada County sheriff's deputies to get to the remote location.
An Ada County spokeswoman told The (Boise) Idaho Statesman roadblocks had been established at various access points to the forest.
Searchers from state, local and federal agencies were combing the area on foot and horseback Friday. A bomb-disposal team was also dispatched to check the abandoned car, which San Diego investigators had suspected could be booby-trapped with explosives.
DiMaggio, 42, is suspected of killing Anderson's mother and possibly her brother, Ethan, 8, Saturday and then setting fire to his home in Boulevard with the bodies inside. DiMaggio was described as a longtime friend of the Anderson family who had recently confessed to having a romantic crush on the high school student.
Charred remains of a child were also found in the ruins of DiMaggio's home; however, they remained unidentified. Gore said the riders Wednesday did not see any sign of Ethan during their chance encounter.
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