CAMP PENDLETON (CBS) — An investigation has uncovered the cause of a deadly helicopter crash at Camp Pendleton last year.

A report finds that a bird strike was to blame in the Sept. 19, crash.

The burned wreckage set off a brush fire that charred more than 120 acres.

Two Marines were killed when the AH-1W Cobra attack helicopter collided with a red-tailed hawk. The bird had a wing span of 4 feet.

The U-T San Diego obtained the report.