The death of a boy in Berks County appears to be the result of a freak accident, state police said Thursday.

The 15-year-old boy became entrapped in a rope swing hanging from a tree in the yard of a home on East Main Street in Union Township, just outside Birdsboro, police said.

The boy's father made the discovery while cutting grass around 6 p.m. Wednesday, according to a neighbor.

The initial investigation has revealed that the boy died of asphyxiation, but an autopsy will be done to confirm that finding, said police, who declined to identify the victim.