The woman who died in an accident on Interstate 5 in Federal Way early Saturday morning was the sister of former Husky and current Boston Celtics star Isaiah Thomas.

According to a release from the Washington State Patrol, 22-year-old Chyna Thomas was heading southbound on I-5 just north of 288th when her 1998 Toyota Camry went off the road to the left jersey barrier. The car landed on the barrier hitting a pole. She was not wearing her seat belt.

She was pronounced dead on the scene.

“We are terribly saddened by the tragic loss of Chyna Thomas. The thoughts & prayers of the entire organization are with Isaiah & his family,” the Boston Celtics said in a post on their Facebook page.

WSP said the crash is under investigation.