A father and son were killed in a snowmobile crash in Hermon early Sunday.

The Maine Warden Service said in a release that Jason Tracy, 33, of Hermon and his son, 10, were killed when the snowmobile they were riding in struck a tree on the edge of a field at about 1 a.m. Sunday.

Maine game wardens, Maine State Police troopers and Penobscot County deputies worked through the morning investigating the crash.

Tracy’s son was wearing a helmet but Tracy was not, the warden service said.

Speed and alcohol were contributing factors in the crash, Warden Lt. Dan Scott said.

The crash remains under investigation.