NORWAY (AP) – A Norway man was killed Sunday after driving his snowmobile into a tree at a high rate of speed.

Richard Fratianne, 61, was riding in a field in Norway with a friend at about 9 a.m. when he passed his friend’s snowmobile at a high speed and drove into some woods at the edge of the field, said Maine Warden Service spokesman Mark Latti.

Fratianne, who was not wearing a helmet, died at the scene, Latti said.

Latti said wardens are investigating whether the accident may have been caused by a medical condition, given the victim’s medical history and the way he drove his machine into a tree without turning.

There have been six snowmobile fatalities in Maine this winter, Latti said.