How a Q-tip and spotless car linked Bryan Kohberger to quadruple murder
Why has Bryan Kohberger pleaded guilty?
Bryan Kohberger has admitted to hacking four University of Idaho students to death as they slept, pleading guilty to four counts of murder Wednesday in a deal that will spare him from death by firing squad. But, there is still no indication about why he committed the cold-blooded crime. LiveNOW's Andy Mac discusses Kohberger's sentencing for the death of four University of Idaho students with attorney Jacqueline Goodman.
Investigators were honing in on Bryan Kohberger as the suspect in the heinous quadruple murders of four University of Idaho students in 2022, but they still needed their smoking gun.
The missing piece – a DNA sample matching the male DNA left at the crime scene – turned out to be a used Q-tip from Kohberger’s father, pulled from the trash outside the home of Kohberger’s parents in Pennsylvania.
Kohberger agreed this week to plead guilty to the stabbing deaths of Kaylee Goncalves, Ethan Chapin, Xana Kernodle and Madison Mogen in their rental home near campus on Nov. 13, 2022.
RELATED: Bryan Kohberger accepts plea deal in Idaho student murders case
The plea deal means Kohberger, now 30, will avoid the death penalty, but it also leaves a lot of questions that could have been answered at trial.
Bryan Kohberger, charged in the murders of four University of Idaho students in 2022, appears for a hearing at the Ada County Courthouse on July 2, 2025, in Boise, Idaho. Kohberger has agreed to plead guilty in exchange for being spared the death pen
Q-tip and spotless car link Kohberger to crime
What we know:
The night of the murders, Kohberger left behind the knife sheath that held the murder weapon, and along with it his DNA. The Q-tip found in his father’s trash matched Kohberger’s DNA, which ultimately led to his arrest. But investigators already had other evidence against Kohberger before they struck investigative gold with the Q-tip.
Kohberger's cell phone began connecting with cell towers in the area of the crime more than four months before the stabbings, lead prosecutor Bill Thompson said, and pinged on those towers 23 times between the hours of 10 p.m. and 4 a.m. in that time period.
RELATED: Bryan Kohberger's motive: What we know after guilty plea
A compilation of surveillance videos from neighbors and businesses also placed Kohberger's vehicle — known to investigators because of a routine traffic stop by police in August — in the area.
Prosecutors say Kohberger, who had begun a Ph.D. program in criminal justice at nearby Washington State University, also went to great lengths to cover up his crimes.
What they're saying:
"The defendant has studied crime," Thompson said. "In fact, he did a detailed paper on crime scene processing when he was working on his Ph.D., and he had that knowledge skillset."
He reportedly drove backroads to his apartment in Pullman, Washington, to avoid surveillance cameras on the major roads and didn't turn his cell phone back on until 4:48 a.m. By 5:26 a.m., he was back in Pullman, Thompson said.
Victim’s family "beyond furious" after Kohberger plea
Bryan Kohberger has reached a plea deal with prosecutors, agreeing to plead guilty to the murders of four University of Idaho students in exchange for avoiding the death penalty, according to multiple media reports on Monday. LiveNOW’s Andy Mac is speaking with Legal Analyst Nicole Deborde.
Later, Kohberger changed his car registration from Pennsylvania to Washington State — significant for investigators who were combing through surveillance camera footage because Pennsylvania law doesn't require a front license plate, making it harder to identify the vehicle.
And by the time investigators did catch up with him weeks later, his apartment and office in nearby Pullman were scrubbed clean.
"Spartan would be a kind characterization. There was nothing there, nothing of evidentiary value was found," Thompson said of Kohberger’s apartment.
The car, too, "had been essentially disassembled inside," he added. "It was spotless. The defendant’s car had been meticulously cleaned inside."
What was Kohberger’s motive?
What we don't know:
Although prosecutors have painted a clearer picture of what happened that night, they still haven’t answered why Kohberger picked that house and those victims. They also haven’t said whether Kohberger knew any of the people he reportedly killed.
"We do not have evidence that the defendant had direct contact with 1122 or with residents in 1122, but we can put his phone in the area on those times," Thompson said, referring to the house number where the murders took place.
What's next:
Some of the evidence that won’t come out at trial might still be found in court documents, but those remain sealed until after a July 23 sentencing hearing. A gag order in place for all attorneys in the case is still in effect as well.
Those documents include witness lists, a list of exhibits, an analysis of the evidence, requests for additional discovery, filings about mitigating factors and various unsuccessful defense motions that sought to introduce alternative suspects, among other things.
It’s not clear whether Kohberger’s motive for the grisly killings will be revealed when the gag order is lifted.
The Source: This report includes information from The Associated Press and previous LiveNow from FOX reporting.