Maine State Police officials said the department is investigating the cause of a crash that killed a man in the Downeast area.Clyde Samuelson Jr., 79, of Columbia, was identified as the victim of the single-vehicle crash along Route 1 in Milbridge. Police said they responded to the area shortly before 2:25 p.m. Wednesday.According to investigators, Samuelson was driving east on Route 1 in a 2011 Ford pickup truck when the vehicle went off the roadway on the north side and crashed into a ditch between Route 1 and the Sunrise Trail.First responders removed Samuelson from the vehicle and rendered medical aid, but he was ultimately pronounced dead at the scene.Police said Samuelson was the only person inside the truck at the time of the crash.Members of the Washington County Sheriff's Office and the Milbridge Fire Department assisted state police at the crash scene.The cause of the crash remains under investigation.