Ohio University has suspended all 15 of the fraternities on campus immediately and indefinitely after allegations of widespread hazing at seven of them, the university announced on Friday. Sigma Pi fraternity was expelled in May following the hazing of 18-year-old Collin Wiant, who died in November. “Ohio University will not put at risk the health and safety of our students,” said Jenny Hall-Jones, the university’s dean of students. “These troubling allegations, which will be thoroughly investigated, indicate a potentially escalating systemic culture.”