Isaiah Thomas's sister killed in Washington car accident

Isaiah Thomas' sister was killed in a car accident on Saturday morning.

Boston Celtics star Isaiah Thomas's sister, Chyna Thomas, died in a one-car accident in Federal Way, Washington's Interstate 5 on Saturday morning, according to Adam Himmelsbach of the Boston Globe. 

The news was first reported by KIRO 7 in Washington state.

Chyna Thomas died at the scene of the accident after her car wrecked around 5 a.m.

A witness said the car was traveling normally at first before it started drifting onto the left shoulder. The car went about 50 feet off the roadway before colliding with a Jersey barrier.

Chyna Thomas was reportedly not wearing her seatbelt.

The Celtics will play the Chicago Bulls on Sunday in Boston. Thomas is still in Boston and did not find out about his sister's death until after practice, according to Mark Murphy of the Boston Herald.