SPOKANE — Autopsies show that two men killed when a small plane crashed into the Spokane River died of blunt impact chest injuries, the Spokane County medical examiner’s office said Friday.

The men who died Thursday have been identified as Lyndon Amestoy, 60, and Richard Runyon, 64. Officials did not know which man was the pilot. The men were underwater for about 30 minutes before divers pulled them free.

The plane, a Piper PA46, remained submerged in the river. A salvage company planned to bring in some air bags that will be inflated to float the aircraft to the surface Saturday so it can be dragged to shore, KXLY-TV of Spokane reported.

The National Transportation Safety Board is investigating the cause of the crash. The men had reported engine trouble and the pilot tried to make an emergency landing at Felts Field — a small public airport along the north bank of the Spokane River.

The state Department of Ecology was called to the scene to oversee cleanup of a leak from the plane’s fuel tank.

Witnesses said they could tell something was wrong with the plane.

“It sounded weird, like it was struggling,” witness David Dexter told The Spokesman-Review.

Richard La Belle was climbing rocks when he saw the crash.

“It didn’t pierce the water, it slapped it,” La Belle said, adding that it sank quickly after hitting the water.

A fire station is located near Felts Field, but a passing freight train prevented emergency crews from immediately getting to the crash scene, Assistant Fire Chief Brian Schaefer said.

It was the second plane crash in Spokane this year.

On Feb. 22, a single-engine Piper Malibu Mirage that had just taken off from Felts Field crashed near the Hamilton Street bridge in east Spokane, killing pilot Michael Clements. A problem with the airplane’s fuel is suspected in that crash.