BOSTON (CBS) — State Police are trying to track down witnesses from a deadly crash last week in the Tip O’Neill Tunnel.

David Dang of Somerville was struck and killed by a passing car on November 25.

Investigators believe Dang had just been involved in a minor collision and had pulled over to the side of the road.

State Police are looking for the other driver involved in the initial minor crash. They say that person was driving a dark-colored, compact, four-door car, possibly a Chevrolet.

Investigators say that person did stop, got out of the car, and had a brief conversation with Dang before driving off.

Dang was struck and killed by another car as he was returning to his car.

The driver who struck him remained at the scene and called 911. He has not been charged.

Police are looking for the driver of this car as a possible witness to a deadly crash in the Tip O'Neill Tunnel.

State Police detectives are also trying to track down the driver and any passengers in a light-colored station wagon, possibly a Subaru that was traveling right behind crash.

State Police are stressing that detectives are only looking for information those witness might have to ensure a thorough investigation.