Philadelphia police are investigating multiple sexual assaults following a similar pattern that were reported this summer in Center City.

According to Philadelphia police, the first sexual assault was reported on July 18 at 6:40 a.m. in the 1900 block of Spruce Street in Center City. Police say the suspect said "good morning, beautiful" to the victim, who was walking her dog at the time, before he sexually assaulted her.

In each case, including three incidents last weekend, the man groped a woman after approaching her from behind, authorities say.