PRICE — A preliminary report by the National Transportation Safety Board sheds little light on what caused a deadly helicopter crash near here.

The NTSB report said the cause of the July 19 crash that killed three men is still unknown.

"A witness observed the helicopter take off toward the south and turn to the west," the report said. "The helicopter was last seen descending slightly as it left the airport boundary. No identified witnesses observed the impact sequence. However, witnesses reported seeing a fireball shortly after the helicopter's departure."

The helicopter contained about 35 gallons of fuel on take-off, the NTSB said. The investigation is ongoing.

The crash killed James Ian Innes, 59, of Salt Lake City; his son, Andrew Innes, 30, of Park City; and George McDaniel, 40, of Idaho Falls.