U.S. News & World Report 6 Relatives Dead in Apparent Murder-Suicide at Texas Home A mass killing where two siblings are the perpetrators is rare, said James Alan Fox, a criminologist at Northeastern University. “In these situations, mass killing, it’s usually one perpetrator,” he said. The Associated Press/USA Today/Northeastern University Mass Killing Database has recorded 452 incidents of mass killings — the slaying of four or more people — […]