SIOUX FALLS, S.D. (KELO AM) - A Sioux man is accused of sexually assaulting a 15-year-old girl at a South Sycamore Avenue apartment Thursday night.     Officer Sam Clemens says 19-year-old Karwo Solo knows the victim and they met at a friend's apartment.     Clemens says Solo allegedly forced himself onto the girl but she was able to free herself and run for help.     She ran to Fire Station Two on South Sycamore where firefighters called police.     Clemens says officers found Solo at the apartment and arrested him for second degree rape.