Maine State Police said Monday that they are investigating the cause of a fatal crash between a motorcycle and a tractor trailer in Hollis last week. The wreck occurred near 718 Cape Road just before 7 p.m. Wednesday, Department of Public Safety spokesperson Shannon Moss said. Motorcyclist Michael Keith, 43, of Limington, was taken to Maine Medical Center in Portland, where he died of his injuries, Moss said. The driver of the tractor trailer, a 25-year-old Biddeford man, was uninjured. Cape Road was closed for about seven hours Wednesday after the crash.