A young woman who was sexually assaulted Monday on the Howard University campus was raped inside a classroom by a person who followed her off a city bus, authorities said Tuesday.

D.C. police said they were searching for the attacker but had made no arrests. In a statement, the university said the 18-year-old woman was participating in a program that was not sponsored by the university.

Police said the attack occurred shortly after 8 a.m. in the 2600 block of Sixth Street NW, near Cramton Auditorium.

A police report obtained by The Washington Post said the woman was aboard a bus when a male passenger she thought she knew from junior high school winked at her. She got off the bus and walked north on Sixth Street and was confronted by the man, police said in the report.

“The complainant reported that the suspect followed her into the school and pushed her into a classroom,” the report said.

The report said the man forced the woman to the floor of the classroom and raped her.

A spokeswoman for Howard University released a statement that said “the location and the circumstances around this case are still under investigation.” The police report said the victim told police she believed the attack occurred in the business school.

The attack comes several weeks after Omar Sykes, 22, a business marketing major, was shot and killed just off campus during what police have described as a random robbery attempt July 4. No arrest has been made in that case.

Since September, Howard University police have dealt with a small spike in violent crime, including armed robberies, thefts and assaults.