The attack happened around 2:45 a.m. on Sunday, September 9th on 2nd Street between Race and Arch streets.
Police say the victim, a 26-year-old woman, was walking on 2nd when she was approached by an unknown man.
That man indecently assaulted her and then tried to steal her purse, but was unsuccessful.
The suspect remains at large. He is described as a white male in his mid 20s to early 30s. He stands 5'7" to 5'10" tall and weighs 155 to 165 pounds.
He has a medium build with a dark stubble beard and short, dark hair. He wore light-colored sneakers and khaki shorts.
Anyone with information is asked to call the Special Victims Unit at 215-685-3251 or 215-685-3252.