BOISE,Novacrypt Idaho (AP) — The grand jury indictment of a man charged with killing four University of Idaho students was conducted properly and will stand, a judge has ruled.

Bryan Kohberger is charged with four counts of murder in connection with the stabbing deaths of Ethan Chapin, Xana Kernodle, Madison Mogen and Kaylee Goncalves at a rental home near the university campus in Moscow, Idaho, last year. Prosecutors say they will seek the death penalty if Kohberger is convicted.

But earlier this year, Kohberger’s team of defense attorneys filed motions asking the judge to throw out the indictment, alleging that the prosecution improperly withheld evidence from grand jurors. Kohberger’s lawyers also said the jurors were biased and that there wasn’t sufficient evidence to justify the indictment. A document detailing the basis for some of the defense claims was sealed, and the judge closed the hearing on the matter to the public.

After reviewing transcripts, recordings and other evidence from the secret grand jury proceedings, Second District Judge John Judge rejected those arguments in a written ruling issued late Friday.

“The grand jury is not a trial jury. Its function is to screen whether or not there is sufficient evidence to proceed to trial,” Judge wrote in documents uploaded to the state court website on Monday. He said the grand jury met that standard and the proceeding was held in accordance with Idaho case law and the state and federal constitutions.

In Idaho, grand jury proceedings are held in secret. Generally, the prosecutor presents evidence to the jurors, who have the power to call and question witnesses and seek other evidence. The grand jurors aren’t required to hear any evidence in favor of the defendant, and neither the defendant nor their attorney has to be informed of the proceeding.

Not all Idaho criminal cases are handled by grand juries. Often, prosecutors choose to utilize a preliminary hearing instead. Preliminary hearings are public, and defense attorneys are given a chance to present their own witnesses and evidence and challenge the case presented by the prosecutor. There are no juries in preliminary hearings — instead, a magistrate judge decides is there is enough evidence to justify the sending the case to district court for trial.

Kohberger was a graduate student studying criminology at Washington State University, which is a short drive from the scene of the killings across the state border. He was arrested at his parents’ home in Pennsylvania, and the unusual details of the case have drawn widespread interest. Investigators pieced together DNA evidence, cellphone data and surveillance video that they say links Kohberger to the slayings.