The announcement Monday of the death of a Massachusetts man who was injured in a snowmobile crash on Feb. 22 brings to seven the number of snowmobilers killed in Maine this winter, prompting the Maine Warden Service to warn riders to slow down.

The leading factor contributing to the crashes is speed, said Cpl. John MacDonald of the Maine Warden Service.

On Saturday, a Lee man was killed in the Penobscot County town of Springfield. John Dorsey, 52, was killed when his machine struck a tree on Buckshot Road, a private plowed road, MacDonald said. Lee’s body wasn’t discovered until just before 11 a.m. Sunday when a man headed to a residence on Buckshot Road discovered the crash scene.

MacDonald said Dorsey had left a friend’s house around 9 p.m. Saturday on his 1999 Arctic Cat Panther 440. Dorsey failed to negotiate a corner and his machine left the road and struck a tree. Dorsey was wearing a helmet.

The snowmobile was still running the next morning despite a significant amount of damage. Game wardens say speed and alcohol appeared to be contributing factors in the crash. MacDonald said notifications to Dorsey’s family were delayed because they were out of state.

The crash remains under investigation.

MacDonald announced on Monday that a Massachusetts man injured in a Feb. 22 crash near Stacyville has died. Duane Carter, 55, of Spencer, was riding with a group on ITS 83 when he collided with a snowmobile driven by a friend.

Six people died in snowmobile-related incidents last winter, according to the warden service. The deadliest snowmobile season was 2002-2003, when 16 people were killed in snowmobile crashes.

MacDonald on Monday reminded riders to slow down and leave the appropriate time and distances while riding to negotiate curves, intersections and other riders.