BOULDER, Colo. (KDVR) — A former University of Colorado Boulder student and Kappa Sigma Fraternity member has been arrested for allegedly sexually assaulting a woman in August.

Ethan Hirsch, 19, was arrested on Sept. 29. He is facing a felony charge of sexually assaulting a physically helpless person.

Hirsch posted a $10,000 bond on Oct. 4.

What the arrest documents say

According to the arrest documents, the alleged incident happened on Aug. 18 at the Kappa Sigma Fraternity annex house at 1453 Broadway.

The Boulder Police Department said the victim reported the incident to police in person on Aug. 24.

The victim told a detective that she was with her roommate at Kappa Sigma around 2 a.m. on Aug. 18 when she saw Hirsch, who she said she knew from high school. She also told police that she was not interested in Hirsch and the two were only acquaintances.

Detectives asked the victim if she had been drinking during the evening and she told them she drank wine and Mike’s Hard Lemonade, but “nothing crazy.”

Hirsch then allegedly asked if he could take the victim on a tour of the house. The victim told detectives that she did not recall seeing the house.

“The victim explained she did remember feeling a hand being placed around her neck, which she demonstrated with her own hand, and being thrown down and later waking up in the morning, feeling if only a few seconds had passed between the time, she felt she was thrown and waking up,” Boulder detectives said in arrest documents.

Police said she told them she was unable to move and he was pushing on her back and her head was into the pillow.

The woman told police that she tried to leave the room and was going to order an Uber ride, but Hirsch told her he would take her home and he did not want her to walk out of the main entrance.

“She described how she thought she should not be in the car, adding she was unsure of Hirsch’s mental state, explaining she did not want to upset him,” arrest documents read. She told police she was also in a lot of pain.

Detectives said they checked surveillance video of the hotel where the victim and her roommate were staying and saw Hirsch drop the victim off. They noted nothing physical happened between the victim and Hirsch in the video.

When the victim was back with her roommate, she explained what had happened. Documents showed that the victim’s friend told her, “dude, you just got raped.”

During a sexual assault exam, nurses noted pink contusions on the woman’s back, along with three abrasions on her shoulder, injuries to her lower legs, abrasions on her lips, and bruises on her thighs, according to the arrest document.

Police said they spoke to several people at the fraternity, as well as the victim’s roommate prior to Hirsch’s arrest.

No toxicology information was provided in the arrest affidavit.

Statement from CU Boulder

We reached out to CU Boulder for a statement, and this is what the university shared with FOX31:

“We are aware of an arrest of a formerly enrolled CU Boulder student involving sexual assault charges. While we cannot discuss specific cases due to privacy laws, our community should know that we take allegations of sexual assault seriously, and those found responsible are held accountable. CU Boulder is committed to continuously improving our prevention and education efforts and our response resources to meet the needs of our campus community. CU has dedicated resources for confidential support and advocacy, safety measures, and investigative response regardless of whether incidents occur on or off campus.”

How to get help if you’ve been sexually assaulted or abused

The Rape, Abuse and Incest National Network said every 68 seconds, an American is sexually assaulted.

“Sexual violence affects hundreds of thousands of Americans each year. While we’re making progress, even today, only 25 out of every 1,000 rapists will end up in prison,” RAINN said.

The National Sexual Assault Hotline has a variety of ways to help you. Whether you are looking for support, advice, information or a referral, the hotline can help you. The number is 1-800-656-4673.