By Mike Dougherty

PHILADELPHIA (CBS) — Philadelphia police are searching for the man they say sexually assaulted a young woman inside her apartment in University City over the weekend and terrorized her for more than two hours.

Investigators say the 22-year-old Drexel University student went to bed in her apartment at about 3:30 a.m. Saturday.

“At some time during the night, she was awakened by an intruder who was already laying in bed with her,” said Philadelphia Police Capt. Mark Burgmann.

Burgmann says the victim screamed but was unable to fight off the suspect.

“We believe the male was inside the apartment for several hours,” he said. “The male finally fell asleep at approximately 7 a.m. The complainant was able to escape her apartment and right outside notified Drexel University police.”

The suspect was able to get away before police arrived.

Burgmann says there was no sign of forced entry. Authorities are asking for the public’s help in identifying the suspect.

Police say the man is described as the following: black male, 25 to 30 years of age, medium complexion, 5-foot-8, medium build, short hair, wearing a green hooded sweatshirt, jeans, and tan boots.

Police say anyone who sees the suspect should not approach him but contact 911 immediately.