By Keith Coffman

(Reuters) – A gunman who fatally shot nine people at an Oregon college in 2015 wrote of his demonic views and how he shared a bond with other mass killers, documents released by authorities showed on Friday.

The self-titled “My Manifesto” by shooter Christopher Harper-Mercer was among documents released by police and prosecutors following a lengthy investigation into the October 2015 mass shooting at Umpqua Community College near the town of Roseburg.

Armed with five handguns and a rifle, Harper-Mercer, 26, stormed into his writing class, killing his professor and eight students, and wounding eight others before being wounded by police. He then killed himself.

U.S. President Barack Obama at the time spoke forcefully for stricter gun control measures after the massacre, the bloodiest in modern Oregon history.

No criminal charges would be filed in the case, Douglas County Sheriff John Hanlin and District Attorney Rick Wesenberg said in a joint statement on Friday.

“All investigative indications are that the shooter acted alone in this incident,” they said. “The shooter died of a self-inflicted gunshot wound to the head after exchanging gunfire with law enforcement officers when confronted.”

In the rambling, six-page manifesto that was found on a thumb-drive, Harper-Mercer wrote of his social isolation which forced him to “align with demonic forces.”

“I had no friends, no girlfriend, was all alone,” he wrote. “I had no job, no life, no successes.”

He also described the affinity he had with other serial and mass killers, including Ted Bundy and the school shooters at Columbine High School in Colorado and Sandy Hook Elementary in Connecticut.

He urged others who have been rejected by society to “give in to your darkest impulses.”

Among the documents released were statements and recordings of police interviews with witnesses, who described the chaotic scene once the gunfire erupted.

Jilliane Michell, an instructor at the college, said she was “terrified” when she heard a volley of gunfire after she left the classroom to use the bathroom.

“I just felt I couldn’t leave the bathroom or I would get shot,” she told detectives.

Michell asked a detective if it was “cowardice” for her to hide during the shooting.

“I don’t think you’re a coward by any means,” the detective said.

(Reporting by Keith Coffman in Denver; Editing by Cynthia Osterman)