The FBI released a report Wednesday with findings from a study looking into domestic terrorists who carried out attacks in the United States without direction from a terrorist group or organization. The FBI calls them “lone offenders.”

According to the FBI, there have been 52 domestic terrorism attacks in the U.S. since 1972. The report gives an overview of offenders' backgrounds and behavioral characteristics and the circumstances surrounding the attacks.

FBI Special Agent John Wyman says there is no one demographic profile for an offender and a holistic analysis is needed to understand the factors that lead an offender to use violence to resolve their issues.

“As a result, there’s no checklist or scoresheet someone can use to say whether this person’s a threat or not,” Wyman said.

The FBI reported that all 52 lone offenders were male, with 21% between 30 and 31 years old.

The report states:

Most offenders were born in the US (n=47, 90%). Four offenders (8%) were naturalized citizens and one offender (2%) was a legal permanent resident. Most offenders were white/Caucasian (n=34, 65%), while the remaining 18 offenders (35%) were divided among five different racial groups.

The study also found that in 25% of all cases, at least one person learned about an offender’s plans to carry out an attack. The FBI says in all those cases, people expressed concern about the offender before the attack.

“Absent this report and others like it, someone could see something and they’re solely relying on their gut feeling or spider sense to say, ‘That doesn't look right,’ or ‘That’s concerning,’” Wyman said. “I think by putting this information out there, it helps people get over that barrier. It gives you something to fall back on to validate whatever your gut feeling was.”

The FBI says 96% of the offenders produced writing or videos meant to be viewed by other people. The report states more than a third of the offenders engaged in “religious seeking at some point before their attack.”

“The ideological offenders are often going to wrap an idea around their personal problems, and they typically want to try and test that idea out on other people,” Wyman said.

FBI Director Christopher Wray says bystander training is needed to help in prevention efforts.

“Bystanders need guidance to recognize concerning behaviors and overcome natural resistance to reporting,” Wray said. “Just as important as early recognition by bystanders is the need to have well-trained, skilled, and competent receivers of that reporting.”

Another key finding in the study stated 25% of lone offenders were formally diagnosed with one or more psychiatric disorders before their attack, with 13% diagnosed afterward. 

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