CANBERRA, Australia (AP) — Crash investigators say a pilot saw an engine malfunction warning signal moments before his helicopter crashed on Australia's Great Barrier Reef last month, killing a honeymooning couple from Hawaii and injuring a Colorado couple.

The Australian Transport Safety Bureau on Wednesday released its preliminary report on the cause of the crash northeast of the Hamilton Island tourist resort on March 21 that killed 79-year-old Peter Hensel and his 65-year-old wife Sue.

Sue Hensel's 33-year-old daughter Emily Sheets and her 34-year-old husband Bobby escaped the crash with minor injuries. The 35-year-old pilot, who has not been identified, was not hurt.

The report said the honeymooners had been "fatally injured," but did not elaborate. The crash investigation is continuing and has not suggested any probable cause.