Bryan Kohberger, known for the Idaho student killings, reportedly gained his initial burglary skills through breaking into homes to support a teenage heroin habit, according to a recent book.

“He developed a heroin addiction as a teenager [in Pennsylvania], leading him to commit break-ins,” crime author James Patterson explained to Lawrence Jones on “FOX & Friends” Wednesday morning. “He had been engaging in this for years, and that mirrors what occurred in Moscow. He entered this house and took the lives of these four promising students.”

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

Both she and Kernodle were employed at the now-closed Mad Greek restaurant, which offered vegan menu choices that the author speculates may have been attractive to Kohberger, who followed a 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.