"Happy Face Killer" Keith Jesperson believes Kohberger's awkwardness and high-profile murder case make him vulnerable, and he's recommending a transfer to Oregon.

In the days after murdering four University of Idaho students in an off-campus home, Bryan Kohberger’s behavior shifted dramatically and investigators would later find that he had fixated on news coverage of the killings and began paying for items in cash – often wearing gloves – as he avoided the area of the murders.

ABC News sat down with Idaho State Police Lt. Darren Gilbertson, the lead detective in the Idaho murders case, after Bryan Kohberger was put behind bars for life.

Despite Kohberger's guilty plea in the Idaho murders, investigators still don't know his motive, who he targeted or where the murder weapon is after he covered his tracks.

The convicted murderer appears gaunt and expressionless in the photo, taken as he begins to serve out multiple life sentences for the murders of four University of Idaho students: Xana Kernodle, 20; Ethan Chapin, 20; Madison Mogen, 21; and Kaylee Goncalves, 21.

She told police that they planned to meet shortly after he stabbed four students, but that they stopped talking because their conversations made her "uncomfortable."

Idaho quadruple murderer Bryan Kohberger transitions from county jail to maximum security prison where inmates with life sentences have nothing to lose

Kaylee’s sister Alivea Goncalves delivered a blistering takedown of Kohberger at sentencing, demanding the slouching psycopath ‘sit up straight’ as she spoke directly to him