University City - January 9, 2009 --Police need help tracking down a man they believe is behind several attacks in recent months. Police describe the attack of two University of Pennsylvania students at the end of last month as "brutal". They said a man forced himself into their apartment on the 40-hundred block of Spruce Street Friday December 19-th. Armed with a gun and knife, he reportedly tortured both girls and sexually assaulted one of them. "It was just violence, rape and robbery," said John Appledorn of the Citizens Crime Commission. Investigators believe the same man may have attacked two women on October 22nd on the 9-hundred block of Clinton Street. They're also linking him to an attempted attack October 21st on the 21-hundred block of Lombard Street. Police said a surveillence camera at an ATM on 50th and Baltimore in Southwest Philadelphia captured video of the suspect. He has used his victim's ATM cards at that location a couple of times, which leads investigators to think he lives in that area. "There's a $5,000 reward, this guy has got to be taken off the street," Appledorn said. The December attack happened at 3 in the afternoon sparking a warning from officials to always be watchful. "You gotta always be aware of your surroundings you know especially apartment buildings and I don't care where it is, what section of the city, outside of the city you know." If you have information about any of these attacks please call 215-546-TIPS. If the tip you have leads to the arrest and conviction of the person responsible you are eligible for the $5,000 reward.