Monday afternoon, former DeKalb County Police Officer Robert Olsen pleaded not guilty of all charges in the shooting death of Anthony Hill, who was unarmed and naked when he was killed. Olsen also waived the formal reading of the charges.

Robert Olsen appeared at an arraignment hearing in a DeKalb County courtroom to answer murder charges filed by DeKalb District Attorney Robert James.

11Alive's Valerie Hoff was in the courtroom and said the hearing was brief, only lasting a few minutes.

Photos | Robert Olsen arraignment met with protesters for Anthony Hill

Hill, 27, a former Air Force veteran, was shot and killed by then DeKalb County Police Officer back in March 2015. Police were responding to a 911 call about a naked man wandering the apartment complex acting erratically. Authorities said the naked man, Hill, lunged at Officer Olsen in a threatening manner.

Photos from the scene

Last October, a civil grand jury recommended more investigation into the fatal shooting. After that decision was announced, DeKalb County District Attorney Robert James said he would take the grand jury's recommendations into consideration.

On Monday, Olsen pleaded not guilty to the charges. It was the first time Hill's girlfriend, Bridget Anderson, came face-to-face with the former officer.

"Just to see him for the first time was really hard," Anderson told 11Alive.

Hill's mother and sister were also in the courtroom, and said if they had the chance to say anything to Olsen, it would be to ask him why he pulled the trigger.

"Why did he do what the did," asked Carolyn Giummo. "(It's) very difficult every day. It’s like it just happened. Being in court and seeing the officer -- there’s not a day that goes by that I don’t think about my son."

Photos | Anthony Hill

Hill's family said they were encouraged to see the legal process move forward after more than a year. They said they hoped the story about their son would lead to better treatment for all mentally-ill people, especially veterans.

Protesters have called for better mental health training for officers after Hill's diagnosis of bipolar disorder was made public. Hill had been struggling after returning home from overseas and was in treatment for mental health issues.

Monday, a group of protesters were outside of the courthouse when Olsen arrived for the arraignment. Some Anthony Hill supporters inside the courtroom tried to confront Olsen and his attorneys as they left the courtroom. Security officers quickly diffused the situation without incident.