State police have concluded their investigation into a violent two-vehicle crash in Durham last month that killed two men.

On the morning of September 21, 2016, a black 2003 Chevrolet pickup containing three men was traveling eastbound on Runaround Pond Road.

As the pickup, owned by Plowman Construction of Gorham, reached the junction of Hallowell Road (Route 9) and Rabbit Road, the operator failed to stop at a stop sign, state police said in a Thursday news release.

As the vehicle entered the junction, it collided with a Volvo dump truck that was traveling southbound along Hallowell Road.

The force of the impact caused the dump truck, owned by Larrabee Construction of Durham, to rotate 180 degrees and tip onto its left side. The pickup rotated violently and two of its occupants were ejected. The pickup also caught fire.

Based upon evidence at the crash site, crash reconstruction, medical records and eyewitness reports, investigators determined that the pickup was operated by Brandon Harthorne, 24, of Cornish, the release said.

Police said Harthorne was not wearing a seat belt and was ejected from the vehicle through the driver’s door. He suffered multiple injuries and died instantly as a result of blunt force trauma of the head.

The front passenger was identified as Jeremy Reardon, 35, of Limington. Police said he was not wearing a seat belt and suffered multiple significant injuries. He was transported by Life Flight to Central Maine Medical Center in Lewiston.

The third occupant of the pickup was sitting in the rear passenger-side seat. He was identified as Malakai Cawood, 21, of Limington. The release said he was not wearing a seat belt and was ejected from the vehicle through the rear driver-side door. Cawood suffered multiple injuries and died instantly as a result of blunt force trauma of the head.

The operator of the dump truck was Clifton Larrabee, 42, of Durham. Clifton was wearing his seat belt but was transported to Maine Medical Center in Portland with serious injuries.

Investigators said mechanical failure, road conditions, speed and the use of drugs or alcohol were not factors in the crash. The release said human error led to the deadly wreck.