The truck and body were found on private property down a long driveway in the 7300 block of Woods Creek Road, about nine miles north of Monroe and about six miles south of Lake Roesiger.
Lt. Susy Johnson of the Snohomish County Sheriff's Office said deputies were dispatched to the scene at about 3:30 p.m. Saturday after receiving a 911 call from a citizen.
The caller told dispatchers that a burned-out truck had been found on the property, backed into some trees, with a body outside.
"We do not currently know if there is a connection between that vehicle and the property it was located on," Johnson said.
Officials did not say whether the body is a man or woman. Johnson said deputies have not determined whether the person is the victim of an accident or foul play.
It's also not clear how long the truck and body have been there.
A residence is located on the property, but no one was home when authorities arrived.
The Major Crimes unit has been called in to spearhead the investigation.
This is a developing news story. More information will be posted as it becomes available.