A 3-year-old boy in Washington state died Thursday after he fell off a lawnmower driven by his father and was struck, authorities said.

The Snohomish County Sheriff Office's Major Crimes and Collision Investigation Unit called the tragedy an accident after finding no suspicious or criminal related evidence. The boy was not identified.

"Witnesses reported that the boy fell off and went under the mower," department spokeswoman Shari Ireton told Q13 FOX. "The boy was pronounced dead at the scene."

Investigators told KOMO-TV that the Snohomish County Medical Examiner will officially determine the child’s cause and manner of death.

The University of Washington Medical Center told Q13 FOX that lawnmowers were the leading cause of foot and ankle amputation to children. They urged that children should never ride on a mower, even if accompanied by an adult.