BOISE, Idaho – Bryan Kohberger may have pleaded guilty to the University of Idaho student murders in Moscow, Idaho, but he gave no other details after admitting to the crimes. Despite a trove of new information released by authorities after his sentencing, key questions remain unanswered. 

For no known reason, he entered an off-campus rental house at 1122 King Road around 4 a.m. Nov. 13, 2022, killing four undergrads inside: Madison Mogen, 21, Kaylee Goncalves, 21, Xana Kernodle, 20, and Ethan Chapin, 20. 

With a gag order lifted and a trove of confidential documents compiled by investigators expected to become public, there may still be more questions than answers after investigators revealed this week that the 30-year-old former criminology Ph.D. student wiped his devices and left no clues as to a motive or which of the students he was targeting and why.

"[The] problem is he had a few weeks head start on hiding his tracks before he ever ended up on their radar," said Joshua Ritter, a Los Angeles defense attorney and Fox News contributor. "That's a lot of times in the hands of a man with some education on police investigative procedures."

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Soil testing also ruled out most of the country from matching a sample found on Kohberger's shovel inside his car when he was arrested at his parent's house in Pennsylvania. It appeared to have come from a riverbed somewhere near Moscow, Idaho, according to police documents made public Wednesday. Detectives, however, were unable to match it to an exact location.

"Obvious questions like, 'where is the knife?' and 'what did he do with his clothing?' still remain," Ritter said.

The murder weapon was never recovered despite extensive search efforts, the case's two lead detectives said at a news briefing Wednesday. They had assistance from the FBI, which tested soil samples to try and narrow down areas to search. But while they recovered a Ka-Bar knife sheath with Kohberger's DNA on it from the crime scene, they never found the matching knife.

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"But the biggest questions — ‘Why did he target that house? What connection did he have to any of the victims? And what was his motive for the killings?’ — the prosecution team has no ideas and does not seem all that interested in finding out," Ritter said.

Despite reporting that suggested Kohberger first eyed Mogen or Kernodle at the Greek restaurant in Moscow where they both worked, speculation that he had followed one or more of the victims on social media or that he had been enraged by his inability to attract women, the only concrete tie police revealed between Kohberger and the victims before the slayings were frequent visits to their home.

The lead investigators, Idaho State Police Lt. Darren Gilbertson and Moscow Police Cpl. Brett Payne, declined to speculate about who Kohberger may have specifically targeted and that, despite his extensive education in criminal justice and criminology, they have not uncovered a motive for the crime.

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When asked directly during Wednesday’s press conference whether investigators have uncovered a clear motive behind Bryan Kohberger’s brutal murders of four University of Idaho students, the response was immediate: "We don’t."

They did, however, reveal that he successfully used third-party software to wipe his devices and thwart their investigation into his digital activity — at least some of it.

They were still able to find records on his phone that showed he tuned into the local police scanner before turning his phone signal off to commit the crimes. They traced him to the victims' house a dozen times before the murders based on phone data and said returned one last time five hours after butchering the victims. They found a selfie on his phone taken shortly after the crime. They used his location and cell data to trace his movements. They ruled out speculation that he posted about the case with a secret Facebook account under the name "Pappa Rodger."

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Judge Steven Hippler, who accepted the plea deal that spared Kohberger from the death penalty without requiring him to explain his actions, called Kohberger a "faceless coward" and suggested that people should move past a motive, which may never be known, and forget the killer outright.

"In my view, the time has now come to end Mr. Kohberger’s 15 minutes of fame," the judge said.

Referencing a judicial predecessor known for finding at least one positive thing to say about convicts at sentencing, he said Kohberger left him at a loss.

"Truth be told, I’m unable to come up with anything redeeming about Mr. Kohberger," he said. "His grotesque acts of evil have buried and hidden anything that might have been good or intrinsically human about him."

Latah County Prosecutor Bill Thompson said part of the reason he offered a deal that didn't require Kohberger to explain himself was because he thought the mass murderer would just lie in an effort to further traumatize the victims' families.

Police caught Kohberger after tracking down DNA evidence found on the knife sheath through cutting-edge methodology known as investigative genetic genealogy. Once they had him in custody, they swabbed his cheek for DNA and confirmed the match. Even without the knife, Gilbertson and Payne said they were confident they would have found him eventually.

They had solid leads tied to the suspect's vehicle, his white 2013 Hyundai Elantra.

Additional documents about the case are expected to be made public by various law enforcement agencies in the coming months. They could continue to reveal new details, but it's doubtful they'll explain the core unanswered questions.

But maybe Kohberger will some day from behind bars.

If he does, it's unlikely he can profit from the story under Idaho law.

Fox News' Lorraine Taylor and Sarah Rumpf-Whitten contributed to this report.