Idaho student killer Bryan Kohberger got his first hands-on experience as a burglar while pilfering homes to fund a teenage heroin addiction, according to a new book.

“He was a heroin addict as a young guy [in Pennsylvania], and he was breaking and entering into houses,” crime novelist James Patterson told Lawrence Jones on “FOX & Friends” Wednesday morning. “He’d been doing it for years, and that’s exactly what happened in Moscow. He broke into this house and killed these four beautiful students.”

Patterson teamed up with investigative journalist Vicky Ward on “The Idaho Four: An American Tragedy,” which dropped earlier this week.

She and Kernodle both worked at the now-shuttered Mad Greek restaurant, which had vegan menu options that the author believes appealed to Kohberger’s meat-free diet.

“He obviously had a big problem with women,” Patterson said, based on roughly 300 interviews he conducted and public documents. “We believe he was targeting Maddie and things had happened… He was going to lose his scholarship.”

Kohberger was pursuing a Ph.D. in criminology at Washington State University – where he reportedly butted heads with other students. After his arrest, the school said it had cut ties.

Kohberger’s defense did not respond to a request for comment.