Underground or "rogue" off-campus groups acting as substitutes for traditional fraternities and sororities are a focus for colleges and universities across the country, NBC News reported.
Last month, Washington, D.C.'s American University expelled 18 students associated with one so-called underground fraternity, Epsilon Iota, citing "a threat to the safety and well-being of our students."
"I think it's unheard of," said Hank Nuwer, a journalism professor at Indiana's Franklin College, who has written books on hazing. "I really can't tell you any other [school] that has done that."
Recent deaths linked to hazing at traditional Greek life groups at Penn State and Louisiana State University have renewed attention on a long-standing issue. But hazing in off-campus groups presents another challenge.