2 dead in Northern California library shooting

Police arrested an 18-year-old suspect in a shooting Monday evening at a Northern California library, which left two dead and one injured, according to the Chico Police Department.

Shots were fired soon after 5 p.m. at the Chico branch of the Butte County Library in Chico, California. Law enforcement took the suspect into custody as he fled the library out the back, Chico Police Chief Billy Aldridge said in a news conference on Monday.

The suspect, identified as Bradley Scott Sayer, was arrested and is currently being held in the Butte County Jail on two counts of murder, according to Chico police.

Officers said the suspect wanted a Columbine massacre-style shooting and did not know the victims, who were all patrons of the library.

On April 20, 1999, two students opened fire at Columbine High School in Littleton, Colorado, gunning down 12 of their fellow students and a teacher before killing themselves.

According to law enforcement officials, Sayer was wearing clothing like that of Columbine killer Eric Harris. And Sayer, the officials tentatively believe, is associated with an online fandom group of mass killers that has been linked to previous shootings. The officials believe he acted alone over his Columbine obsession.

"The incident this evening was obviously very sad, traumatic for a lot of people," Aldridge said in the news conference. "Very traumatic for our community."

Eight total rounds were fired, with one victim fatally struck at the main entrance and the other in the back of the building, police said.

One of the victims, 46-year-old Cody Hull, was accompanying a friend's daughter to the library when he was killed, his brother told ABC News.

"I'm completely devastated to have lost my brother," Benjamin Heneberry said.

A 74-year-old man was also killed, police said.

Additionally, a girl was taken to the hospital with minor injuries, Aldridge said. She appears to have been injured by broken glass and has since been released, police said Tuesday.

Authorities found two additional firearms in the suspect's vehicle, which was parked outside the library, police said.

All branches of the Butte County Library are closed on Tuesday.

Law enforcement said they are continuing to investigate the shooting, and there is no current danger to the public. They believe the shooter acted alone. The Chico Police Department is collaborating with the Butte County Sheriff's Office and the FBI in the investigation, which remains ongoing.

ABC News' Megan Fahrney, Matthew Claiborne and Chris Looft contributed to this report.