On July 4, an airplane which serves as an air ambulance crashed in the U.S. state of Texas, killing all five people on board, officials said.

The two-engine plane was en route to Midland, Texas, when it crashed in an open field around 12 a.m. about a mile east of Alpine-Casparis Municipal Airport in west Texas, according to the U.S. Federal Aviation Administration (FAA).

The dead included a 78-year-old patient, his wife, two flight nurses and the pilot, local media reports said.

The pilot had tried to make an emergency landing when the plane crashed and burned, the Texas Department of Public Safety said.

An investigation was underway.