The man accused of firing shots and setting a fire inside the Colorado Supreme Court building earlier this month used drugs and was experiencing hallucinations before the incident, a police affidavit says.

The shooting happened on January 2 after 1 a.m., when police say a suspect who fled a two-car accident scene shot out a window of the Ralph L. Carr Colorado Judicial Center and went in, according to a news release from the City of Denver. Police say the man forcibly took keys from an unarmed security guard, fired shots in the building and set a fire in a stairwell.

Brandon Olsen, 44, surrendered at the scene almost two hours after the vehicle crash, authorities said. According to a probable cause affidavit from police, Olsen told police that prior to the shooting, he had taken several Fentanyl pills and smoked methamphetamines. The document says Olsen indicated he had a history of drug abuse and relapse.

Olsen has been charged with first-degree arson, aggravated robbery and second-degree burglary, according to court records obtained by CNN. All are felonies.

His preliminary court hearing is scheduled for February 20.

Olsen, who lives in Arizona, drove to Denver on New Year’s Eve to visit his teenage son, the affidavit says.

Before the incident, Olsen was driving his car and “felt like police were chasing after him” after he had taken the drugs, he told detectives in an interview, according to the document.

“He attempted to evade these people by driving faster but he could not lose them,” it says. “At one point while in downtown Denver he crashed his car into another car at an intersection.”

After the crash, Olsen grabbed his Taurus 9mm pistol from the back seat of his car and ran towards the nearby state Supreme Court building, firing a shot at a window and crawling through the broken glass to gain entry, the affidavit says.

Olsen then grabbed keys from a security guard and accessed several floors and the building’s roof using the stairwell and a master key, the affidavit says.

While on one of the higher floors, Olsen used his lighter and paper to start the fire, later telling detectives he decided to do it “because he thought people were after him,” the affidavit says. At that point, the smoke was billowing, so he fired several shots into the building’s glass windows to clear some of the smoke, it says.

After starting the fire and noticing a police presence outside of the building, Olsen called 911 and then walked outside, where he was taken into custody by police, the affidavit says.

Olsen acknowledged to detectives he believed he was hallucinating, saying he had never had the experience before, according to the document.

Police took Olsen to a hospital for evaluation before questioning because he complained of chest pains, the document says.

CNN has reached out to Olsen’s attorney for comment.

The downtown building – which houses the state’s Supreme Court, Colorado Court of Appeals and other judicial agencies – had just two people in it at the time of the incident, authorities said.

The security guard was sitting alone at the information desk before investigating a noise, the affidavit says. The guard then was held at gunpoint by the suspect while trying to use a key to open a door for the pistol-wielding man, according to the court document.

The other person in the building who is mentioned in the affidavit is a woman who was working in an office. She told detectives she left when she heard the fire alarm and said she didn’t witness the shooting or fire.

Police said no one was injured during the ordeal, but “there is significant and extensive damage to the building.”