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Kidnap suspect, girl sought in Idaho's River of No Return Wilderness

The nationwide manhunt for murder suspect James DiMaggio, who is believed to have kidnapped 16-year-old Hannah Anderson, now centers on wooded terrain in Idaho. Authorities remain concerned DiMaggio may be armed with explosives. NBC's Joe Fryer reports.

The search for a kidnapping suspect and the teenage girl believed to have been abducted has narrowed to a remote Idaho area known as the Frank Church-River of No Return Wilderness.

Investigators have set up checkpoints in the back-country area northeast of Boise where a horseback rider said he spotted a man and woman believed to match the description of Amber Alert suspect James Lee DiMaggio and 16-year-old Hannah Anderson, Ada County sheriff's spokeswoman Andrea Dearden said Friday.

Officials suspect DiMaggio, 40, set fire to his own house, killing a woman and her son, whose body was positively identified Friday night, and kidnapped Hannah. Authorities in several states, Canada and Mexico have been looking for him.

The horseback rider told authorities he saw an adult man and a teenage girl on Wednesday evening near Morehead Lake, Dearden said. The man told police he found the couple odd but not dangerous.

“There was nothing immediately alarming about this pair,” Dearden added.

At a news conference earlier Friday, San Diego County Sheriff Bill Gore said both people spotted on Wednesday appeared in good health.

Uncredited / AP

This composite photo provided by the San Diego Sheriff's Department shows: James Lee Dimaggio, 40, Ethan Anderson, 8, and Hannah Anderson, 16.

"As far as we know, it didn’t look like she was being held against her will,” Gore added.

The pair was spotted on foot equipped with camping gear about six to eight miles from where DiMaggio's car was found Friday morning.

The Nissan Versa was found in a remote, mountainous area outside of the city of Cascade, covered with brush and without any license plates. A check of the car's vehicle identification number was performed and confirmed it was DiMaggio's car, the sheriff said.

In Idaho, an Ada County sheriff's spokesman said no explosive devices were found in or near the car. Authorities had said they feared that DiMaggio might have homemade bombs. The car remained parked at the trailhead Friday night while authorities waited for a crew from the San Diego County Sheriff's Department to arrive.

Gore said he was confident the girl would be returned safely.

“She was alive on Wednesday and we hope that law enforcement will find them up in the mountains there and return them safely,” Gore said.

At a news conference in San Diego County, Sheriff William Gore said a car matching the description of the vehicle in the Calif. kidnapping case was found in a remote area of Idaho.

The Frank Church-River of No Return Wilderness covers more than 3,500 square miles and is known for its rivers, deep canyons and mountains. 

Hannah Anderson has been missing since her mother’s death.

On Sunday, police discovered the burned remains of Christina Anderson, 44, in a log cabin-style home in Boulevard, Calif., about 60 miles east of San Diego. Along with Anderson’s body, police also found the body of a child. The remains were positively identified Friday night as those of Ethan Anderson, 8, the San Diego Sheriff's Department said late Friday. He had been listed as missing.

Amber Alerts were issued in Oregon and Washington on Wednesday for the two kids after DiMaggio’s car was believed to have been spotted in Northern California. An alert was also posted in Nevada on Thursday. 

The FBI and various state and local law enforcement agencies are assisting in the investigation. 

DiMaggio is described as white, 5 feet 9 inches, 150 pounds, with brown hair and brown eyes. He may have shaved off a mustache and beard, detectives said.

Sheriff's officials told NBC San Diego that Christina Anderson had a “close platonic relationship” with DiMaggio. Neighbors told the station had he moved to the area five years ago. A neighbor told The Associated Press that Christina and her husband, Brett Anderson, had recently separated. 

San Diego sheriff’s officials said DiMaggio has had an “unusual infatuation” with Hannah.

“That is kind of a working theory, that it may be something of a motivator,” San Diego County sheriff’s Capt. Duncan Fraser told NBC San Diego. “It’s definitely something that we're looking at.”

Marissa Chavez, 15, told The Associated Press that a couple of months ago she had witnessed DiMaggio tell her friend that he had a crush on her and would date her if they were the same age, as they drove home from a gymnastics competition.

“She was a little creeped out by it. She didn’t want to be alone with him,” Chavez told the AP.

NBC News' Erin McClam contributed to this report.