AMHERST – A Patten man was killed Monday afternoon when he lost control of his dump truck on Route 9 in northern Hancock County, sending the vehicle rolling into a ditch and pinning him inside.

Daniel Williams, 56, died before emergency responders could take him to a local hospital, according to Maine State Police Trooper Barry Curtis.

Curtis said Monday at the scene that the man appeared to have lost control of the vehicle as he was driving west on a relatively straight stretch of Route 9. Several witnesses spoke with police, Curtis said, but by late Monday night, the cause of the accident had not been determined.

“We’re still trying to determine if there was another vehicle involved,” he said. “From the looks of it, he almost had it corrected. The truck probably rolled over a couple of times.”

A large black skid mark could be seen on the roadway, leading to the ditch where the overturned truck ended up. A white sheet covered the cab while the man’s body remained inside at about 4:30 p.m., nearly two hours after the accident occurred.

Curtis said police were waiting for an official with the state medical examiner’s office to arrive, but he said it looked as if the man died from internal injuries. Williams was not wearing a seat belt.

The trooper said the man was driving a 10-wheel dump truck for Emery Lee & Sons Inc., a Millinocket trucking and construction company. The company was doing work for Lane Construction Co. and Williams had just left a job site farther up Route 9 beyond Aurora, where crews were resurfacing the roadway.

Shortly after the accident occurred, first responders called for a LifeFlight helicopter, which landed near the scene at about 3 p.m., but it was too late.

A state police accident reconstruction specialist was called in to assist with the accident investigation, Curtis said Monday night.

Speed and alcohol were not considered factors in the crash, he said.

The accident resulted in the closure of busy Route 9 for about half an hour, causing extensive backups in both directions, Curtis said.