(NewsNation) — Bryan Kohberger’s mother described him as “my angel” in a newly surfaced interview with authorities, insisting “my son would not do this” after his arrest in the 2022 Idaho student killings. 

The interview is cited in a new book by retired FBI agent Christopher Whitcomb, “Broken Plea: The Explosive Search for Truth Behind the Idaho Murders,” which draws on investigative files, court records and Kohberger’s writings from jail.

In the book, Whitcomb reveals an interview with Kohberger’s mother, Maryann Kohberger, the day he was arrested at his parents’ home in Pennsylvania.

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“My son would not do this. I will stake my life on that. There’s a mistake; something is wrong somewhere. And that’s what I believe. And that’s what I know in my heart,” she told FBI investigators.

She described her son as nonviolent, reserved and a “homebody” with few friends who focused on school and avoided drinking or partying, adding she had no concerns about his behavior before his arrest.

Kohberger is serving a life sentence after accepting a plea deal in July, admitting to the murders of Kaylee Goncalves, Maddie Mogen, Xana Kernodle and Ethan Chapin at the University of Idaho.

Prosecutors tied Kohberger to the killings through DNA on a knife sheath, confirmed via a familial match from trash. They also cited cell data placing him near the home and offline during the murders, plus surveillance of his white Hyundai Elantra and a roommate’s sighting of a masked man.

The book also details a series of abstract letters Kohberger wrote from jail to his family and pet.

In one letter to his dog, Scout, he referenced an unseen “communication,” signing off as “Brother.”

“Earlier, you and I, unbeknownst to you, ‘communicated’ I have no doubt that your Heart was conscious of what I intended . . . “ he wrote.

A letter to his sister stated, “Dear Amandayzz, In the abstract sense, and via intuitive capacities, the August effect can be analogized to the gravitation of Hearts promise unto the green pastures ahead . . . Always in your Heart, Bernnzz.”

In a longer letter to his family, Kohberger talks about “ascending to new peaks” and finding clarity through a “Singular Heart.” He signs off with multiple nicknames, including “Buddy” and “Brother.”

“We have traversed many once-novel territories, finding that, when all else may seem variable/entropic, it is the one constant from which clarity and serenity are ever-accessible,” he wrote.

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