(NewsNation) — Prosecutors are publicly linking University of Idaho murder suspect Bryan Kohberger’s DNA to a knife sheath found at the crime scene, according to new court filings.

It was previously known that genealogical DNA connected back to Kohberger’s father.

“A traditional STR DNA comparison was done between the STR profile found on the Ka-Bar knife sheath and Defendant’s DNA. The comparison showed statistical match,” according to the court filing.

Kaylee Goncalves, 21, Madison Mogen, 21, Xana Kernodle, 20, and Ethan Chapin, 20, were stabbed to death in an apartment shared by the three women in November 2022.

Last month, Kohberger didn’t verbalize a plea in court, leading a judge to enter not-guilty pleas on charges of murder and burglary in connection with the November stabbings. Kohberger’s lawyers want to evaluate whether the grand jury that indicted him was biased.