David Bogenberger was found unresponsive Nov. 2 at the fraternity house, with a blood-alcohol content of 0.351 percent, which DeKalb County Coroner Dennis Miller said led to an arrhythmia, the NIU student newspaper Northern Star reported Monday.
Miller ruled the death accidental.
The DeKalb Police Department said five fraternity members face felony hazing charges and 17 people face misdemeanor hazing charges.
An investigation into the events before Bogenberger's death confirmed that the fraternity hosted "Parent's Night," where pledges were provided with alcohol, the police said in a release.
"All 22 are charged with a form of hazing," DeKalb Police Lt. Jason Leverton said. "Those five [facing felony charges] we felt were principally involved in the planning of the evening. ... They had more responsibility in the fraternity. They could have ended the evening at any time."
NIU announced that Pi Kappa Alpha and 37 unnamed students faced charges of violating the university's Student Code of Conduct, the Northern Star said. The university said its investigation found that Pi Kappa Alpha hosted an unsanctioned social event for pledges Nov. 1. The university said fraternity leaders did not officially register the event with their national chapter or NIU.
Bogenberger's family, in a statement issued Monday, told university administrators and fraternities "to stop the hazing and initiation rituals that claimed David."