ATLANTA (AP) — Georgia's highest court ruled Monday the prosecution of a white former Atlanta-area police officer who fatally shot an unarmed, naked, mentally ill black veteran may go forward.

The Georgia Supreme Court rejected arguments by Robert Olsen's attorneys that the charges against him should be dismissed because the principle of grand jury secrecy had been violated by the presence of extra, unnecessary people during the grand jury proceedings.

Olsen, a DeKalb County police officer at the time, shot Anthony Hill on March 9, 2015, while responding to a call about a naked man behaving erratically outside a suburban Atlanta apartment complex.

A grand jury indicted Olsen in January 2016 on charges of felony murder, aggravated assault, violation of oath of office and making a false statement.

Olsen's attorneys in June 2016 filed a motion to dismiss the case, saying "unauthorized" people had been present in the grand jury room. During a hearing on the motion in September 2016, attorney Don Samuel said those included multiple people from the district attorney's office, an expert witness and a court reporter who didn't transcribe anything but a statement by the officer.

The presence of all those people, especially people from the district attorney's office, could have discouraged grand jurors from asking questions, Samuel said, though he made it clear that he did not believe anyone was purposely intimidating grand jurors.

DeKalb County Superior Court Judge J.P. Boulee ruled in October 2016 there aren't grounds under Georgia law to dismiss the indictment, but he allowed Olsen to appeal that decision to the high court.

"No unlawful conduct is shown in this case, and no prejudice is demonstrated by the manner in which the prosecutor conducted the evidentiary stage of the grand jury proceedings," Georgia Supreme Court Justice Robert Benham wrote in the unanimous opinion Monday.

Benham wrote that unlike in federal grand jury proceedings where clear rules specify who may be present while evidence is presented, there are no such limitations under Georgia law or procedural rules. While the preservation of grand jury secrecy is well-recognized in Georgia, Benham wrote, the court didn't believe the need for grand jury secrecy was compromised in this case.

But Benham was careful to note that the opinion does not mean prosecutors may allow spectators — including journalists or school classes — to watch grand jury proceedings. Prosecutors should "take care to conduct grand jury proceedings in a manner that does not discourage witnesses from testifying fully and frankly, that protects against the risk that the accused might flee to avoid prosecution, and that ensures persons who are ultimately not indicted are not the subject of public ridicule," the opinion said.