Four teenagers are facing gang assault charges after an assault Wednesday afternoon. According to Rochester police, someone called 911 around 3:30 p.m. to report an assault that was being streamed on Facebook Live. Officers found the victim, a man in his 30s, with a head injury on Clinton Avenue. Police tracked down the suspects after four simultaneous foot chases. A 19-year-old, a 17-year-old, and two 16-year-olds are charged with first degree gang assault. The victim is being treated for serious injuries.