A teenage gunman connected to the chilling Friday afternoon shooting at Pittsburg Center Station that left two men injured has turned himself in, authorities confirmed. After days of urgent manhunt and investigative work that included sifting through BART’s extensive surveillance footage, the 17-year-old assailant surrendered Tuesday morning to BART Police detectives in Walnut Creek, as stated on BART Police Department’s Facebook page, and is expected to be booked into Contra Costa County Juvenile Hall.