Denver police hope a new composite drawing will help identify a man who may have groped four women near the University of Denver.The latest incident occurred on Thursday.A woman told police she was walking along South High Street around 9:15 p.m. when a man she had passed ran back up to her and grabbed her behind.DU issued Crime Alerts to let students know about four similar gropings since the school year started."An even bigger concern is this individual may graduate into attempting more serious crimes. So it may start as a groping now and could very well be an attempt of a sexual assault down the road," said Detective John White with Denver police.On sorority row near the school, 7NEWS found women walking in pairs, as the school has recommended, and fully aware of the situation."I don't walk home alone like I used to last year. (I'm) just a little more careful when I walk at night," said Vanessa Nguyen, a DU sophomore. "I shouldn't be walking home alone in the first place. But I'm just being extra careful now with what's been going on around campus."The man believed to be the suspect is white and stands 5 feet 8 inches tall, with a thin build. Police said he is roughly 19 years old and was wearing a gray hoodie with black stripes down the arms.If you have any information, Crimestoppers has offered a $2,000 reward.You can call 720-913-STOP (7867) and remain anonymous.