(NewsNation) — A former FBI agent believes Bryan Kohberger would definitely kill again had he not been arrested for the 2022 murders of four University of Idaho students.

“When looking at serial killers, they have a pattern of behavior that they’re trying to do to satisfy some fantasy or need they have,” Robin Dreeke told NewsNation “That one selfie he took in the bathroom, it was the only time he showed emotion, and it was taken supposedly right after the murders. He’s going to do that again to get that same emotional response most likely.”

Dreeke added that Kohberger knew exactly what he was doing because he planned and calculated the murders. He said Kohberger was likely surprised he was caught because he thought he’d committed the perfect crime.

“His one failing was the DNA on the thumb snap of the knife sheath, because without that, this would have been a near-perfect crime that he would have gotten away with,” Dreeke said.

Kohberger accepted a plea deal Wednesday in which he admitted to fatally stabbing Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin in a home in Moscow, Idaho, on Nov. 13, 2022. Sentencing is set for July 23.