Police yesterday showed surveillance videos of a man seen riding a bike in the area of Girard Avenue, then following Sabina Rose O'Donnell toward her home shortly before she was sexually assaulted and strangled last week.

The man, described by Homicide Capt. James Clark as a "person of interest," is black, of medium build and medium to tall in height. He was wearing a white tank top and blue jeans, and was seen cruising the area at the edge of Northern Liberties from about 2 to 2:50 a.m. June 2.

A white tank top, similar to the one the man was wearing, was recovered in the grassy lot where O'Donnell's naked body was discovered, Clark said.

He said earlier this week that DNA was recovered from O'Donnell's body and from the "different clothing items" found at the crime scene. The victim's clothing also was found in the lot behind where she lived, on 4th Street just north of Girard.

O'Donnell, 20, was a popular waitress at PYT restaurant in the Piazza at Schmidts. About 2 a.m. on June 2, she left a friend's house near Front and Girard and borrowed a friend's bike to ride home.

In one video clip police showed yesterday, a man in a white tank top was seen riding a bike on 4th Street at 2:50 a.m., according to the time recorded by the surveillance camera. He traveled south past Girard. The victim, police said, was then seen riding a bike north on 4th Street and crossing that same intersection.

The man then turned around and rode north on 4th, appearing to follow the victim.

In other video clips, the same man was seen riding his bike on Girard near 5th Street about 2:15 a.m. Later, he traveled south on Front Street, then turned right onto the sidewalk on Girard.It was after that he spotted O'Donnell and began to follow her.

The videos are posted at: www.phillypolice.com/news. Police are eager to talk with the man on the bike, whom they believe lives near Girard. Tipsters can call detectives at 215-686-3334.

There is also a $25,000 reward for information leading to the killer's capture and conviction.