Chicago and University police are investigating an allegation of criminal sexual assault January 15 during Bar Night, a weekly party at the Alpha Delta Phi fraternity house. The possible involvement of drugs has been raised in the investigation.

University police arrived at the house in response to a call at 1:03 a.m. Thursday morning. According to a press release last week from the Alpha Delta Phi alumni organization, fraternity members called 911 after a student who was a guest at the house was reported to be in distress. The student was transported to the emergency room in an ambulance.

“We are cooperating fully with all authorities, including the University, as they investigate this incident,” Alpha Delta Phi alumni association president Roger Deschner wrote in the release.

“This is a very private and personal matter for everyone involved. I can assure you that Alpha Delta Phi takes the well-being of its guests very seriously, and when a situation does arise, we follow the risk management training provided by our international [organization],” said fourth-year Jacob Marshall, president of the University of Chicago chapter of Alpha Delta Phi, in an e-mail to the Maroon.

The fraternity has not held Bar Night in recent weeks. The weekly event is a campus institution that draws crowds of undergraduates for beer and socializing at the fraternity house on South University Avenue.

An incident of criminal sexual abuse was reported at the same location on January 10, but the matter is no longer under investigation.