What evidence did defense lawyers challenge in the Kohberger case during pretrial hearings and appeals?
Executive summary
Defense lawyers in the Bryan Kohberger proceedings repeatedly targeted the prosecution’s DNA and genetic‑genealogy trail, the legality of multiple searches and digital‑data seizures, and the admissibility of several behavioral or circumstantial items — including Amazon purchase records and an autism diagnosis — while also pushing venue, pretrial publicity and alternate‑perpetrator/alibi issues; judges have rejected many suppression efforts but left other disputes for trial or sealed hearings [1] [2] [3] [4].
1. DNA and investigative genetic genealogy: the central technical attack
The defense mounted sustained challenges to the DNA evidence that led investigators to Kohberger, questioning the accuracy, legality and chain‑of‑custody of testing and the use of investigative genetic genealogy to generate leads, arguing each step could be tainted or unreliable; prosecutors and judges, however, repeatedly defended the procedures and a judge denied motions to exclude key DNA evidence, saying the disputes were largely fodder for cross‑examination rather than exclusion [5] [1] [2].
2. Search warrants, Franks hearing and Fourth Amendment arguments
Defense filings sought to undermine the warrants and the circumstances that produced critical physical and digital evidence, requesting a Franks hearing to probe alleged false or misleading statements in warrant affidavits and arguing some investigative phases lacked proper warrants; the court denied the Franks motion and expressed skepticism about the defense’s constitutionality claims while leaving some issues for further proceedings, and judges found no evidence of misrepresentation in warrant applications in at least one ruling [1] [2].
3. Digital evidence seizures: phone carriers, cloud accounts and a USB drive
Kohberger’s lawyers moved to suppress or limit use of voluminous digital records seized from AT&T, Google, Apple, Amazon and a USB drive, arguing Fourth Amendment violations and contesting the relevance of location and device data; judges have largely allowed prosecutors to use those materials while noting suppression challenges could become subjects for cross‑examination rather than wholesale exclusion [1] [6].
4. Amazon purchase history and who bought what
Pretrial fights included whether jury members may hear Amazon account shopping and product searches tied to Kohberger’s account, with defense counsel arguing the data do not reliably show who actually purchased or used the items and asking the court to permit expert testimony to explain ambiguities; the judge signaled the defense may challenge provenance and ownership at trial and allowed some contesting of that evidence while reserving final rulings [3].
5. Behavioral and medical evidence: autism diagnosis and death‑penalty implications
Defense lawyers sought to introduce Kohberger’s autism spectrum disorder diagnosis as a mitigating or explanatory factor — including arguments that it should disqualify him from the death penalty — and litigated whether jurors could hear about the diagnosis and how it might explain courtroom demeanor; courts have considered those issues in pretrial hearings, and the defense has persisted in pressing the diagnosis both for mitigation and for context around perceived behavior [7] [3].
6. Identification, eyewitness description and alternate‑perpetrator/alibi theories
The defense attacked eyewitness and circumstantial identifiers — from a surviving roommate’s “bushy‑eyebrows” description to plans to present evidence of alternate perpetrators — arguing such descriptions are unreliable and that sealed filings show proposed alternate‑perpetrator evidence; judges have limited some witness descriptions from the jury and repeatedly warned the defense to meet statutory requirements for alibi claims, at one point ruling Kohberger could not present an alibi where no one could vouch for his whereabouts, while allowing the defense to pursue sealed offers of proof on alternate suspects [3] [8] [4].
7. Venue, publicity and juror bias: procedural challenges to trial fairness
Beyond evidentiary skirmishes, defense attorneys repeatedly sought a change of venue, a continuance and other remedies arguing pervasive pretrial publicity (including documentaries, books and media coverage) and leaks would prejudice jurors; they produced juror surveys and experts on pretrial bias, prompting the court to weigh venue change and mitigation measures even as judges declined some defense requests and emphasized voir dire procedures to screen impartial jurors [9] [4] [6].