Notre Dame Security Police (NDSP) alerted students in an email Wednesday night that a sexual crime occurred over the weekend.
Police said a student was "forcibly fondled" at a social gathering in a campus residence hall Friday night.
A third party reported the incident to NDSP on Tuesday.
Police advised students to remain alert of their surroundings and watch out for friends in order to reduce the chance of sexual assault.
"Please continue to keep in mind that sexual assault can happen to anyone at any time, and that college students are more likely to be assaulted by an acquaintance, meaning that the person perpetrating the assault could be part of the campus community," the email stated.
