DeOrr vanished in July 2015
Credit: Courtesy Jessica Mitchell

Two-year-old DeOrr Kunz vanished in the wilds of Idaho. Subscribe now for an inside look at the search for the little boy and what his parents think happened to their son, only in PEOPLE.

Since 2-year-old DeOrr Kunz went missing during a family camping trip nearly a year ago, investigators have turned their attention toward the boy’s parents.

In January, more than six months after DeOrr disappeared in a remote area of the Idaho mountains known as Salmon-Challis National Forest, DeOrr Kunz Sr. and Jessica Mitchell, both 26, were named suspects by the Lemhi County Sheriff’s Office.

“The primary problem is they’re being less than truthful,” Sheriff Lynn Bowerman tells PEOPLE.

Bowerman says their stories have been inconsistent and have changed multiple times. Still, he says the parents were cooperative – until they were named as suspects.

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Meanwhile, Mitchell’s grandfather, Robert Walton, and his fishing buddy, Isaac Reinwand, who were also on the trip, have also been questioned. Walton suffers from pulmonary issues and Reinwand retained a lawyer immediately following the trip. (Calls to Reinwand’s lawyer were not returned.)

“No one has been cleared,” Lemhi County chief deputy Steve Penner tells PEOPLE.

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Kunz has wondered if his son was taken by a stranger or taken by an animal, but Bowerman doesn’t believe either of those theories.

“We don’t believe it’s an abduction – either human or animal,” he says.

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In their search of more than a two-mile radius around the campsite, investigators have not found blood or clothing.

“We don’t have any physical evidence at this time,” Bowerman says. “We need to find this child.”