Genetic genealogists say unusually abundant DNA on discarded knife sheath sped capture in Idaho student murders
Othram investigators told a conference that 'hundreds of times' more DNA than normal on a Ka-Bar sheath allowed rapid family-tree leads that helped identify Bryan Kohberger.
Genetic genealogists working on the University of Idaho student murders said an unusually large amount of DNA recovered at the scene accelerated their investigation and helped produce the leads that ultimately pointed to the suspect.
David Mittelman, founder and chief executive of forensic genetics firm Othram, told attendees at the CrimeCon conference in Denver that the laboratory found "hundreds of times" more DNA than is typical for such cases on material recovered in the quadruple homicide in Moscow, Idaho. The abundant material included a DNA sample on a Ka-Bar knife sheath discarded at the crime scene, which Othram used to generate investigative leads.
Mittelman described the discovery as "a catastrophic deal," meaning the volume and quality of genetic material were sufficient to allow rapid and detailed genealogical analysis. He said the sample produced a profile indicating a "multigenerational" American family mix, enabling analysts to construct family trees and move quickly from broad population-level information to a narrower set of potential relatives.
Othram's work generated leads that investigators used in the probe that ended with the arrest and later guilty plea of Bryan Kohberger in connection with the deaths of four University of Idaho students. Authorities have said the knife sheath sample was among the forensic traces that played a role in establishing a link to Kohberger.
Mittelman told the conference that the defense in court sought to limit discussion of the DNA findings, saying, "That's why the defense didn't want to talk about it." He said early genealogical leads did not produce an immediate identity but did rapidly point investigators to a particular extended family group.
Forensic genetic genealogy combines DNA sequencing from crime-scene material with genealogical research and publicly available DNA databases to identify possible relatives of an unknown donor. The method has been used in numerous high-profile cold cases and recent homicide investigations; its effectiveness depends heavily on the quantity and quality of recoverable DNA and on the presence of related profiles in reference databases.
Investigators and the laboratory team have said the volume of DNA recovered in the Moscow case was far greater than typical, which reduced some of the technical obstacles that can complicate genealogical reconstruction when samples are degraded or mixed. That abundance, together with traditional investigative work, contributed to the timeline that led to charges and a subsequent guilty plea in the case.
The investigation into the Moscow killings drew national attention after the November attacks on University of Idaho students. Authorities have released limited public detail about specific aspects of the forensic work, saying only that a combination of DNA evidence, genealogical leads and conventional investigative steps formed the basis of the identification and arrest.
Mittelman and other forensic geneticists emphasized at the conference that the success of genealogical methods varies by case. In Moscow, investigators have said the unusually plentiful DNA material materially shortened the time required to develop actionable leads.