A professed Ku Klux Klansman became the first American to be convicted of federal radiation weapon charges on Friday when a jury found him guilty of plotting to kill Muslims with a modified X-ray machine, The Guardian reports.

According to prosecutors, 51-year-old Glendon Scott Crawford and an accomplice tried to create a weapon they described as “Hiroshima on a light switch” to expose Muslim communities to lethal doses of radiation.