FBI blames ‘bystander effect’ for mass shooter who murdered nine

Connor Betts, who killed nine people in a shooting in Dayton, Ohio, reportedly was fantasising about going on murder sprees, becoming a serial killer and contemplating murder-suicide scenarios for at least a decade before his attack, according to the FBI.

The agency revealed the information on Monday as it announced the conclusion of its investigation into the August 2019 shooting.

According to the FBI report, Betts had a “history of obsession with violent ideations with mass shootings and expressed a desire to commit a mass shooting”, but did not share details of his violent fantasies with any of his friends or family members.

According to The Associated Press, the FBI blamed “bystander fatigue” as a possible explanation for why Betts's family and friends may not have noticed his worrying state of mind.

In the report, the FBI said that bystander fatigue described “the passivity, inaction, or inattention to concerning behaviours observed by individuals who have a close, interpersonal relationship to a person of concern due to their prolonged exposure to the person's erratic or otherwise troubling behaviour over time”.

Betts was killed by police half a minute after he began his attack on Dayton's busy entertainment district. He was using an AR-15-style rifle with extended ammunition magazines, allowing him to kill nine people, including his sister, before he was killed.

According to the FBI report, it is still unclear if Betts intended to kill his sister or if she simply got caught up in his crossfire.

Following the shooting, alarming details about Betts began to surface. Classmates claimed he had been suspended years prior for making a hit list and a list of female classmates he wanted to rape.

“It’s baffling and horrible that somebody who’s been talking for 10 years about wanting to shoot people could easily, so easily, get access to a military grade weapon and that much ammo,” Hannah Shows, one of the classmates included on Betts’s rape list, said.

But Dayton Police Chief Richard Biehl told the AP in August that “nothing in this individual’s record that would have precluded him from getting these weapons”, despite the troubling school suspensions.

Betts's gun and ammunition were bought for him by a friend, Ethan Kollie. The FBI report said there was no evidence to suggest Kollie had any idea what Betts was planning.

Kollie eventually pleaded guilty to other unrelated federal firearms charges and was sentenced to two and a half years in prison.

Family members of four of the victims of the shooting sued Kyung Chang Industry USA, the company the produces the extended ammunition magazine Betts used. The families argued that the product's only function is to make killing more efficient.