(Federal Way, WA)  --  Authorities say a woman who was killed in a crash in Federal Way, Washington Saturday morning was the sister of former University of Washington and current Boston Celtics star Isaiah Thomas.  Police say 22-year-old Chyna Thomas was heading south on Interstate 5 north of 288th when her car went off the road.  The vehicle landed on a barrier and hit a pole, and Thomas died at the scene.  The crash is still under investigation.