CUSTER COUNTY, Okla. (KFOR) – A Weatherford, Okla., man died Friday from injuries he suffered when he was struck by an unknown vehicle near Clinton in Custer County.

Oscar Washa, 60, died at AllianceHealth Clinton Hospital in Clinton, according to Oklahoma Highway Patrol.

Washa, a pedestrian, was struck on the Interstate 40 service road a half-mile west of Mile Marker 71 and approximately three miles east of Clinton, according to OHP officials.

It is unknown who or what vehicle struck Washa. He was struck sometime between 8 a.m. and 9:30 a.m. on Friday.

The deadly accident remains under investigation.