From MSP News:

Massachusetts State Police are investigating a crash on Route 93 southbound in Dorchester, between Exits 13 and 12, that resulted in the death of a pedestrian.

Preliminary investigation indicates that the deceased victim, an adult male, was struck by a vehicle as he was walking on Route 93 at approximately 2:30 AM. The victim was walking on the highway after his own vehicle struck the guardrail and apparently became disabled, prompting him to exit his vehicle. He was determined to be deceased on scene.

The vehicle that struck the pedestrian, which contained two occupants, stopped after hitting him. Subsequently, while that vehicle was stationary, it was struck by another southbound vehicle. The two occupants of the stopped vehicle sustained serious injuries and were transported to a Boston hospital. The driver of the last vehicle involved, the one that hit the stationary vehicle, was determined to be operating under the influence and was taken into custody.

All southbound lanes remain closed at this time for the crash investigation and reconstruction. We may have to temporarily close northbound lanes to accommodate an evidentiary search related to the crash.

The investigation is being conducted by Troop H of the Massachusetts State Police, the State Police Collision Analysis and Reconstruction Section, the State Police Crime Scene Services Section, the State Police K9 Unit, and the State Police Detective Unit for Suffolk County.

No further information is being released at this time.