A woman in her 50s was killed by her own auto after another driver hit it outside the Market Basket in Westford Thursday, according to the Middlesex County District Attorney’s Office.

Ryan’s office said she was in her 50s.

Authorities say the woman was standing behind her vehicle when another motorist hit it, pinning her underneath.

Westford police, the Middlesex DA and the state police Collision Analysis and Reconstruction Section are investigating the incident. As a result, the vehicle rolled backwards and pinned the woman underneath.

The driver who hit the woman’s auto remained on scene.

Witnesses told WBZ-TV’s Beth Germano that other cars honked to warn the driver.

The incident happened in near Market Basket at Cornerstone Square, which is located near the intersection of Route 110 and Boston Road at Interstate 495 Exit 32.

No further information is now available.