Image by adl A screenshot of a video game produced by New Mexico school murderer William Atchinson depicting the killing of a Jewish man

William Atchinson, a 21-year-old gas station attendant, entered Aztec High School in northern New Mexico on December 7 disguised as a student. He embarked on a shooting spree which killed two students and injured several others, before killing himself.

Atchinson did not give a reason for his actions, but it was later revealed that had been investigated by the FBI last year after making online comments about mass killings.

In a report published Monday, the Anti-Defamation League noted that Atchinson was also fixated on anti-Semitic fantasies of killing Jews.

“Atchison frequently manipulated video games such as Grand Theft Auto to create scenes, from which Atchison would post screenshots to his account, of people killing Jews or people intended to appear to be Jews,” the report stated. “These graphic images would frequently be accompanied by equally graphic language from Atchison, such as ‘KILL THE JEW,’ ‘RUN OVER THE JEW,’ ‘toten der jude,’ ‘FUCKING DIE JEW,’ ‘JEW-HUNTING,’ ‘RUN LITTLE JEW!!!’

He was also versed in anti-Semitic language and used phrases such as “the goyim know,” which are meant to point to a Jewish conspiracy.

“Had Atchison lived in a city with a significant Jewish population, it is even possible the tragedy he caused might have taken an anti-Semitic form instead of the shape that it did,” the ADL concluded.

Contact Nathan Guttman at guttman@forward.com or on Twitter @nathanguttman