Philadelphia police hope distinctive lettering on a jacket will help them find the man who attacked two University of Pennsylvania students last week after forcing his way into their West Philadelphia apartment.

The Special Victims Unit has released grainy pictures of the man using an ATM machine in West Philadelphia. Although the suspect's face is not discernible, the jacket has the lettering of the brand name ENYCE. Police believe the jacket is chocolate brown with yellow lettering.

Additionally, the Citizens Crime Commission is offering a $5,000 reward for information leading to the arrest and conviction of the attacker.

To collect the reward money, tipsters must call the commission at 877-345-TIPS. Callers may remain anonymous and will receive a code to collect the reward money.

Police believe the assailant, who also may have attacked a Center City woman as well, appears familiar with the area, and in both cases entered secured apartment buildings.

The latest attack occurred about 3 p.m. in the 4400 block of Spruce Street. The 22-year-old victim was forced at knifepoint back into her apartment, where she was bound and gagged with duct tape as the assailant rummaged through the apartment.

About 4:15 p.m., the victim's 24-year-old roommate arrived at the apartment. She was bound, gagged and sexually assaulted. The assailant also stole laptop computers, cell phones, iPods and a bank card.

The assailant had a goatee at the time of the attacks, and is in his mid- to late 20s and about six feet tall.

Police said the attacker resembled a man who forced a woman and her boyfriend into her apartment in the 900 block of Clinton Street on Oct. 22, bound and gagged them, then raped the woman and robbed them.

Police are continuing to search through other unsolved cases for similarities.

Contact staff writer Barbara Boyer at 215-854-2641 or bboyer@phillynews.com.