A University of Colorado student was arrested after reportedly raping a drunken female student after being set up as “dates” for a sorority event in January.

Zachary Orion Roper, 19, is facing one charge of sexual assault, a Class 4 felony.

According to an arrest affidavit, the named victim was in a sorority and attended a “date dash” event in Loveland on Jan. 31 in which members were required to bring a date.

The woman was set up with Roper by another member but had never met him before the event. According to the affidavit, the woman was drinking along with Roper and others before going up to Loveland, and did not have a clear memory of most of the night.

The woman said the next thing she remembered after drinking before heading to the event was waking up with Roper sexually assaulting her.

Witnesses told police the woman was sent to the sorority house in an Uber with Roper when she became too intoxicated, per the sorority’s policy. But the Uber driver told police Roper changed the address from the sorority house to his own apartment during the ride.

The driver said the woman was asleep for most of the ride, and needed help getting out of the car due to her level of intoxication.

Another sorority member who had been told to expect the woman to arrive at the house became concerned when she never arrived, and went to Roper’s apartment with several other members after getting the address from someone who knew him.

The women told police they walked into Roper’s bedroom to find him sexually assaulting the woman, and got her out of the room and to a hospital for a sexual assault examination.

Roper’s roommate also witnessed Roper having sex with a woman that night who was later identified as the named victim.

Roper has a ticket for providing false ID in Boulder, but has no other criminal history, according to the affidavit. He is identified as a history student on CU’s online database.

He remains in custody and is set for a bond hearing today.

Mitchell Byars: 303-473-1329, byarsm@dailycamera.com or twitter.com/mitchellbyars