BOSTON -- The Massachusetts State Police are looking for witnesses to Thursday's fatal four-vehicle crash on Route 2 in Lexington.

The crash resulted in the death of a Gardner woman and injuries to four other people.

A preliminary investigation indicates that at 2:11 p.m. a 2003 Chrysler PT Cruiser operated by Shannon Gwiazda, 33, of Gardner, was heading eastbound on Route 2 when it veered to its left, crossing the grass median into westbound lanes.

The Chrysler struck three oncoming vehicles -- a 2008 Cadillac CTS sedan, a 2009 Kia sedan, and a 1999 Ford pickup truck -- before coming to rest along the wood line at the side of the highway.

State Police are still investigating why Gwiazda veered onto the opposite side of the highway.

They are asking that any motorists who witnessed the crash, or who observed the dark red Chrysler PT Cruiser on Route 2 eastbound before the crash, contact the State Police Barracks in Concord at (978) 369-4100.

Gwiazda sustained fatal injuries and was pronounced deceased at the scene. The Cadillac’s driver, Gina Ashe, 47, of Harvard, and the Kia’s driver, Theresa Lamoureaux, 51, of Maynard, were taken to Leahy Clinic in Burlington with serious injuries.

The pickup’s driver, Mark Saffie, 52, of Methuen, was not injured. Two passengers in the Kia, Eileen Kramer, 54, of Stow and Mary Tessari, 55, of Maynard were taken to Leahy Clinic with minor injuries.