Missing teenager Elizabeth Thomas was finally located Thursday after a search that lasted more than a month. Thomas and the man who allegedly kidnapped her, Tad Cummins, were found in a remote part of northern California after a man became suspicious of their behavior and tipped off police.

“The girl wasn’t really looking at me or anything and he was always dominating the conversation,” Griffin Barry, the man who called the authorities, told "Good Morning America" Friday. “That kind of clues people in.”

He noted that Cummins attempted to “keep [Thomas] away” from other people. The two identified themselves as John and Joanna when they met Barry at a gas station and told him they needed money and a place to stay. Barry put them up in a cabin before seeing photos released by Tennessee investigators that showed pictures of Thomas and Cummins.

“I had a photo of him that was the amber alert,” said Barry. “I was like, that’s definitely the guy, and then we saw the car and it matched up as well.”

Authorities made their way to the area where they found Thomas and arrested Cummins. Thomas was “apparently healthy and unharmed,” according to Maury County, Tennessee district attorney Brent Cooper, who told reporters Thursday that their main concern was “how she is emotionally and mentally.”

Thomas, 15, was a student at Culleoka Unit School in Maury County, where Cummins, 50, was a health science teacher. Thomas and Cummins were seen kissing inside his classroom by an unidentified student in January, sparking an investigation by school administrators and police. The teenager left her home March 13 to go to a nearby restaurant where authorities believe she was taken by Cummins. Thomas reportedly told one of her siblings on the morning of her disappearance that if she was not home by dinner, someone should call the police.

Tennessee investigators cautioned that, despite the inquiries into their relationship, the situation was not romantic.

“She is 15, a child. He is 50, a grown man. She’s a high school freshman. He’s a former teacher. This is, and was, not a romance,” Tennessee Bureau of Investigation director Mark Gwynn told reporters shortly after the two went missing. “This was manipulation solely to benefit Tad Cummins. This is not a fairy tale. This is a case of kidnapping.”