On November 13, 2022, my daughter and I had breakfast in Moscow, Idaho, a Dad’s Weekend tradition from her years at Washington State University. We drove through the University of Idaho campus before returning to Pullman.
Less than an hour later, a 911 call brought Moscow police to a house on King Road, only blocks from where we had been. Inside were four murdered University of Idaho students — Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin. One of the victims’ sisters and my daughter were sorority sisters. The man police would eventually identify as the killer lived in Pullman.
That kind of proximity stays with a father.
Bryan Kohberger was 28 and studying for a doctorate in criminology at Washington State. Seven weeks after the killings, police arrested him at his parents’ home in Pennsylvania. How investigators got from an unknown assailant to Kohberger illustrates both the extraordinary evidentiary trails created by modern technology and the privacy questions that accompany them.
It began with video. Detectives canvassed homes, apartments and businesses and reconstructed the movements of a white sedan seen repeatedly near King Road around the time of the murders. At Washington State, officers found a white 2015 Hyundai Elantra registered to Kohberger.
That was essentially traditional police work with new witnesses: cameras instead of people. The car had traveled on public streets, and much of the video came from private cameras.
The vehicle helped lead investigators to Kohberger and then to his cellphone. With judicial authorization, investigators examined historical cell-site records. His phone stopped communicating with the cellular network at approximately 2:47 a.m. and reappeared at about 4:48 a.m. During that gap, cameras recorded the white Elantra around King Road. Subsequent tower connections helped reconstruct the phone’s movement toward Pullman.
Here the privacy protection was stronger. In Carpenter v. United States, the Supreme Court recognized that extensive historical cell-site information can reveal so much about a person’s movements that police generally need a warrant to obtain it. The evidence remained available, but the government had to establish legal grounds to get it.
Then came DNA. Investigators recovered a knife sheath beside one of the victims containing a single-source male DNA profile. Kohberger was not in CODIS, the FBI system used to compare crime-scene DNA against qualifying profiles collected through the criminal justice system, so investigators turned to genetic genealogy.
That raised a different privacy issue. Kohberger had not voluntarily submitted his DNA to a genealogy company. Relatives had, and because relatives share DNA, their decisions revealed information about him. Investigators used those relationships, family trees and public records to narrow the possibilities.
By then, separate investigative trails-vehicle, cellphone, and genetic evidence- were converging on a suspect. Investigators recovered discarded garbage from the Kohberger family home in Pennsylvania, and DNA testing indicated that a male in the household was overwhelmingly likely to be the father of the man whose DNA was on the sheath.
Garbage carries its own privacy rule. In California v. Greenwood, the Supreme Court held that people generally have no reasonable expectation of privacy in garbage placed outside for collection.
Different legal rules governed video, cellphone records, genealogy and discarded DNA, but together they produced an extraordinarily detailed evidentiary picture.
Police created almost none of that trail. Consumers did.
We install cameras, carry cellphones, submit DNA to discover our ancestry, drive identifiable automobiles and discard objects containing biological material. Modern life generates enormous amounts of information about us whether police ever look at it or not.
That brings us to the latest fight over police technology: automated license-plate readers such as Flock.
Opponents call these networks a dragnet because they record enormous numbers of vehicles. Their strongest argument concerns how much information they collect. Retention, access, information sharing and the ability to reconstruct someone’s movements deserve serious scrutiny.
But the Kohberger investigation illustrates the other side of the equation.
Moscow detectives initially had video of a white Hyundai Elantra but no readable license plate. Make, model, and color can describe thousands of vehicles, forcing investigators to identify and eliminate owners with nothing to do with the crime.
A reliable license-plate read collected by companies like Flock can reduce thousands of possible vehicles to one, allowing police to concentrate on the car the evidence actually identifies.
Even a mistaken plate read is a lead, not proof. If investigators are looking for a white Hyundai Elantra and the plate returns to a Ford pickup, the evidence does not match.
That paradox is largely missing from the dragnet argument.
A surveillance system may collect information about many innocent vehicles while greater precision simultaneously reduces the number of innocent people subjected to police scrutiny. The privacy calculation should consider both sides of that ledger: how much information technology lets government collect about innocent people, and how much better evidence from innocent people government allows investigators to exclude.
That Sunday morning, my daughter and I were leaving evidentiary trails too. Our car traveled on public streets. Our phones communicated with cellular towers. Thousands of parents, students and residents were doing the same.
None of that made us suspects. Evidence does not merely implicate people; it eliminates them.
Civil libertarians are right that technology can give government extraordinary power and that the Fourth Amendment must continue to place guardrails around its use. But the Kohberger investigation demonstrates that privacy and effective policing are not mutually exclusive. Technology gives investigators new tools; the Constitution and the courts establish the legal rules for their use.
And when four young people have been murdered, we should expect police to use every lawful tool within those boundaries to find out who did it.
Steve Smith is a senior fellow in urban studies at the Pacific Research Institute, focusing on California’s ongoing crime challenges.