(NewsNation) — A grand jury indicted Bryan Kohberger on four counts of first-degree murder and one count of burglary in connection to the killings of four Idaho college students.

The grand jury indicted Kohberger Tuesday with the same charges prosecutors announced in December.

Prosecutors took the case against Bryan Kohberger before a grand jury instead of going through with an initially scheduled preliminary hearing. In criminal cases, both procedures can be used to determine whether or not the prosecution has sufficient evidence to bring criminal charges against someone.

Kohberger, a graduate student studying criminal justice in Washington, was accused of stabbing four Idaho college students to death in November. Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin were found stabbed in an apartment near the University of Idaho. Mogen, Goncalves and Kernodle lived in the apartment with two other roommates, while Chapin, Kernodle’s boyfriend, was staying over for the night.

It’s not clear why prosecutors opted for a grand jury in this case, but there are significant differences between a grand jury and a preliminary hearing. Most notable is that grand jury proceedings are secret and the defense does not get the opportunity to question witnesses or hear the case presented.

In the Idaho case, one of the two surviving roommates, Dylan Mortensen, reportedly witnessed Kohberger in the house that night, without realizing anything had happened to her housemates, attributing noises she heard to partying. Both roommates have remained quiet about the case and it’s possible prosecutors used a grand jury to avoid having them face Kohberger ahead of a trial.

Kohberger’s team attempted to subpoena one roommate, Bethany Funke, for the preliminary hearing but her lawyers pushed back on the grounds that a preliminary hearing is meant to find probable cause to charge someone, not to serve as a mini-trial.

Using a grand jury also delayed prosecutors having to make their evidence public in the case against Kohberger. If the grand jury does find probable cause to indict, however, it’s likely more information will be made public during the discovery process, when prosecutors are obligated to turn evidence over to the defense team.

Kohberger is facing an arraignment on Monday, May 22.