By: KIRO 7 News Staff

SKAGIT COUNTY, Wash. — A plane with only the pilot on board crashed Saturday evening into the Skagit River near the I-5 Bridge in Mt. Vernon, police said.

Officials said the single-engine plane crashed about 6:05 p.m. under unknown circumstances.

Witnesses told officers the plane dived nose first, authorities said.

Mt. Vernon police said responding agencies found the plane in the water on the south shore, where the 75-year-old pilot was helped onto the riverbank and treated by medics for minor injuries.

Police said the FAA and the National Transportation Safety Board will lead the investigation into the crash.