BUTLER COUNTY, Pa. -- Investigators said the human remains found in a roadside ditch in Muddy Creek Township of those of an older man.

Police said the bones were in the ditch for at least three years.

Investigators said they have not been able to determine a cause of death because of the decomposition of the bones.

State police in Butler said the human remains were discovered early Thursday afternoon in a ditch at the eastbound exit ramp of Route 422, where it intersects with Route 528 in Muddy Creek Township.

William Ream, a contractor with IA Construction, made the discovery while surveying the area.

Channel 11 News spoke with Ream, who said the remains "were right on top of the ground" with "leaves or nothing on them."

"We're working to determine whose bones they are," said Steve Ignatz of the Pennsylvania state police. The remains were removed Thursday night and are being examined at Mercyhurst College.