PRINCETON, N.J. (CBSNewYork) — A woman attending a Princeton University reunion event was sexually assaulted on campus.

WCBS 880’s Kelly Waldron reported officials said the woman was attending the reunion weekend and was staying on campus at Spelman Hall when she was sexually assaulted at 2 a.m. on Sunday.

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Even in daylight, many Princeton students said they are being told to stay in groups following the assault, CBS2’s Emily Smith reported.

“They just notified us that a sexual assault happened on campus and let us know criminal charges are being pressed,” senior Cameron Platt said.

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The victim has not been identified publicly, but authorities told CBS2 the suspect is described as a 5-foot-9 black male, weighing 170 pounds, with facial hair and a mole on his face. He was wearing a t-shirt and shorts.

The Mercer County Prosecutor’s Office and the Department of Public Safety are investigating the incident.

University officials are advising students to be alert, report suspicious behavior, avoid walking alone and use the buddy system when staying in a building after hours. It’s alumni weekend at the university, which means there are 25,000 students on campus for various events, compared to the usual 5,000.

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