CNN  — 

The gunman who opened fire in Dayton, Ohio, this weekend had an obsession with violence and mass shootings and had expressed a desire to commit a mass shooting, Dayton Police Chief Richard Biehl said Tuesday.

“(He was) very specifically seeking out information that promotes violence,” FBI Special Agent in Charge Todd Wickerham added.

Unlike the El Paso shooting, which the alleged gunman appears to have described as part of an anti-immigrant crusade, authorities still do not know what motivated Connor Betts to open fire early Sunday morning in a popular nightlife district in Dayton.

But comments from authorities, memories from former classmates and posts on his apparent Twitter account show that the gunman took a deep interest in violence – and, as in many American shootings, had easy access to powerful firearms.

Armed with a .223-caliber high-capacity rifle with 100-round drum magazines, Betts fired 41 shots in less than 30 seconds, killing his sister as well as eight seemingly random bystanders in the area, police said Monday. He was killed by police officers on patrol 30 seconds after he opened fire.

In a statement, the Betts family said they were “shocked and devastated” by what happened. They are cooperating with law enforcement and asked for privacy while they mourn the loss of their daughter and son.

Classmates say he kept a hit list

Former high school classmates said that he had a “hit list” of people he wanted to kill or rape. He was in a “pornogrind” band with extremely graphic, violent lyrics. And authorities searching his family home found writings that expressed an interest in killing people, two law enforcement sources told CNN.

But the writings did not indicate any racial or political motive, sources said.

In addition, a Twitter account that appears to belong to Betts retweeted extreme left-wing and anti-police posts, as well as tweets supporting Antifa, or anti-fascist, protesters.

The most recent tweet on the @iamthespookster account was on August 3, the day of the shooting, when he retweeted a post saying, “Millenials have a message for the Joe Biden generation: hurry up and die.”

The user’s Twitter bio reads: “he/him / anime fan / metalhead / leftist / I’m going to hell and I’m not coming back.” One tweet used the hashtag #HailSatan.

A friend of Betts and his sister said Betts was comfortable around guns and would teach people how to shoot safely.

“He enjoyed shooting,” the friend told CNN. “He seemed to have an interest in guns, how do they work, that sort of thing.”

Another person, who asked not to be named for privacy reasons, said some of the names on the hit list were female students who, like her, turned him down for dates.

She said Betts often simulated shooting other students and threatened to kill himself and others on several occasions.

“He loved to look at you and pretend to shoot with guns, guns with his hands,” she said.

Bellbrook Police said Betts had been arrested for operating a vehicle under the influence of alcohol in 2016.

In the hours before the Dayton shooting, the Twitter account “liked” several tweets about a shooting in El Paso that left 22 dead, including one supporting gun control and others that called the El Paso shooting suspect a “terrorist,” and a “white supremacist.”

The account retweeted messages supporting Sens. Bernie Sanders and Elizabeth Warren, as well as posts against ICE agents, including one that said, “these people are monsters,” and multiple posts condemning police, and supporting Antifa protesters, who often use violent tactics.

There were also many tweets of selfies, photos with a friend and ordinary memes and nonpolitical content.

The account was suspended by Twitter on Sunday evening. A Twitter spokesperson would not comment on the account, only saying in a statement, “We’re proactively removing content that violates our policies and will be engaged with law enforcement, as appropriate.”

Former classmates say gunman had a ‘hit list’ in high school

Connor Betts is shown with his sister Megan. Police said Betts killed Megan and eight others Sunday.

As a high school student, the gunman had a “hit list” of classmates he wanted to “kill” or “rape,” said former students who said they were told by school officials they were on the list.

Spencer Brickler said a counselor at Bellbrook High School in Ohio told him he and his sister were on Connor Betts’ hit list. Brickler recalled sitting on a school bus about nine years ago when he saw Betts getting escorted away by officers investigating the threats.

“He was kind of dark and depressive in high school,” said Brickler, who was a freshman when the school counselor told him about the hit list. He said he had no idea what prompted Betts, then a sophomore, to put him or his sister on the list.

Several of Betts’ former classmates told CNN that they recalled Betts being removed from the school for at least a year, but that he later returned to Bellbrook High.

The shooter later attended Sinclair Community College in Dayton but was not enrolled in the summer term, the school’s president Steve John