Authorities announced Thursday that they had discovered human remains at the spot where an Australian military chopper crashed into the water off the nation’s northeast coast.

On the evening of July 28, while participating in a multinational military exercise, an MRH-90 Taipan helicopter crashed not far from the Whitsunday Islands, killing all four crew members on board.

The remains were discovered by a remotely operated underwater vehicle, according to Lieutenant General Greg Bilton, the army’s chief of joint operations, who spoke to media in Queensland.

They were discovered along with the helicopter’s wreckage, which included pieces of the cockpit, some 40 meters (130 feet) below the water’s surface.

According to Bilton, the debris field “consistent with a catastrophic high impact” and that the identification of the human remains would likely wait until further wreckage was discovered.

Strong currents and unfavorable weather that was projected to linger well into the following week further hindered search team efforts, he noted.

The cause of the crash is still being looked into, although search crews have not yet located the helicopter’s black box.

Bilton added, “It’s a challenging undertaking, but we will try everything in our power to find it — the black box is vital to helping us understand what’s truly occurred.

Before the helicopter crashed, all communications were “normal,” he noted.

Defence Minister Richard Marles stated on Monday that the helicopters would not fly again until the crash inquiry was finished, which led to the grounding of Australia’s Taipan fleet in the wake of the accident.

The Australian military was already planning to transition to Black Hawks at the end of this year in place of the troublesome Taipans, which had a troubled past.