Update, June 30, 2025, 6:30 ET: Bryan Kohberger has agreed to plead guilty to all charges in the murders of the Idaho Four. The plea deal allows him to avoid the death penalty in exchange for serving four consecutive life sentences for the murders.

What made their deaths all the more terrifying was how elusive their killer seemed — until a sudden arrest made everything even scarier.

Sometime after midnight on November 13, four University of Idaho students — Xana Kernodle, Ethan Chapin, Madison Mogen, and Kaylee Goncalves — were all viciously attacked while sleeping in an off-campus townhouse. They were each, as eventual criminal charges would reflect, “stabbed and murdered with premeditation with malice and forethought.”

Throughout the seven tense weeks that followed, the case now known as the Idaho student murders rocked the small town of Moscow, Idaho, became a riveting true crime obsession, and sparked a global media frenzy.

But although everything that happened after their deaths would become international news, the lead-up to the quadruple homicide was completely uneventful. And so, nothing seemed to stick: There were no suspicious actions, changes, or alarming behaviors prior to the murders, and no immediate suspects, no big compelling clues, no key witnesses in the aftermath. An unknown intruder or intruders had simply entered the house, stabbed to death four of the six sleeping students inside, and then quietly slipped into the night.

Still, as the University of Idaho community struggled to come to terms with the killings and cope with their fear of the perpetrator, local and federal investigators were hard at work. By late December, despite the massive amount of resources devoted to the investigation, along with a stream of steady case updates, the case appeared to be on the verge of going cold. But on December 30, Moscow police announced they’d made an arrest in the case.

Bryan Kohberger, 28, had no apparent connection to any of the victims. Instead, he was a graduate student at a neighboring university, with an unsettling history and an obsession with true crime. The abrupt identification of the alleged killer, and the excavation of his personal background, meant that one of the most senseless, shocking crimes in recent memory became even more tragic.

Had four devoted friends — two of whom were dating, two of whom were lifelong best friends — lost their lives to a would-be serial killer?

The probable cause affidavit for the arrest, as well as the wealth of information that has since trickled out about the case and the alleged perpetrator, sheds new light on an extraordinarily horrific crime and the equally extraordinary criminal investigation that followed it. What finally led to Kohberger’s arrest was simply excellent investigative work: a mix of well-organized policing, groundbreaking forensics using genetic genealogy, and old-fashioned detective work. As Kohberger heads to trial this fall, the secrets of the criminal they caught are still being unearthed.

The murders

Xana Kernodle, Ethan Chapin, Madison Mogen, and Kaylee Goncalves were all University of Idaho undergraduates, all involved in the campus Greek system, and all fast friends. Kernodle, 20, was a bubbly junior majoring in marketing; she was dating Chapin, 20, a triplet and a fun-loving sports management major. Mogen and Goncalves, both 21, had been inseparable since the sixth grade. They did everything together: lived together, went to school together, and, ultimately, died side by side.

On the night of Saturday, November 12, 2022, everything seemed normal. Kernodle and Chapin went to a party at the Sigma Chi fraternity; Mogen and Goncalves went out to a bar, then hung out at a food truck for a bit. By 2 am Sunday, according to the probable cause affidavit, everyone had gathered at the house on King Road where Mogen, Goncalves, and Kernodle lived with two other roommates. Goncalves, as reported in January by Dateline, had recently moved out of the townhouse as she prepared to graduate early and take a job in Austin, Texas, but she’d returned for the weekend to hang out with Mogen. Months later, this news would fuel public speculation that whoever was watching the house saw her return — and saw it as an opportunity.

The three-story house was accessible primarily by a secure door with a coded entry on the bottom floor, as well as by a sliding glass door on the main level (second floor) of the house. The lower entry was locked, but the sliding glass door might have been more easily accessible.

At 4 am, Kernodle ordered Jack-in-the-Box; at 4:12 am, she was on her phone, surfing TikTok. Sometime in the next few minutes, the attack began. She tried to fight off her attacker — but by 4:25 am, she and her boyfriend would both be dead.

Note: the following section contains disturbing details of the crime.

The killer attacked on the second and third floors of the house, entering each of the victims’ rooms for separate attacks — but he left the roommates on the main and lowest floors alive. He used a large Ka-Bar knife of the style used by the US Marine Corps.

Nearby surveillance footage captured audio of the attacks around 4:17 am, including distressed sounds and barking from Goncalves’s dog. As revealed in the affidavit, one roommate told police she heard noises and crying, but didn’t understand what she was hearing. Although she opened her door repeatedly to see what was happening, she saw nothing alarming — though she did report hearing Goncalves say, “There’s someone here.” Some time later, over sounds of crying coming from Kernodle’s room, she heard a male voice saying, “It’s okay, I’m going to help you.”

The third time she opened her door, it was to the sight of a man clad all in black and wearing a mask, walking toward her. As she stood in “frozen shock,” the killer walked by her room; it’s unclear whether or not he saw her. With his face mostly covered, the roommate noted the only thing she could see clearly:........

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