The tragedy of Flight JT610 continues to expand its deadly toll with the death of an Indonesian rescue diver who lost his life while searching the Lion Air jetliner’s second black box.

News of the death of Syachrul Anto, 48, came on Saturday as authorities revealed divers had reported seeing the fuselage and engines of the crashed jetliner on the sea floor.

They also reported a ping locator had detected a signal thought likely to be coming from the cockpit voice recorder.

Anto died on Friday while searching for 189 victims of the crashed plane, search and rescue agency Basarnas said.

“Deepest condolences for the passing of a humanitarian hero from the Indonesian Diving Rescue Team,” chief officer Muhammad Syaugi said in a news release.

It was not immediately clear how Anto perished. His family had chosen not to conduct an autopsy and asked for his remains to be buried immediately, Basarnas spokesman Yusuf Latif told Reuters.

Among other missions, Anto was also one of the main divers involved in the search for an AirAsia jet that crashed off Borneo in late 2014.

Rescue divers have been crucial in recovering human remains and pieces of the near-new Boeing Co. 737 MAX that smashed into the sea early on Monday, 13 minutes after it took off from Jakarta.

As of Saturday a total of 73 body bags, few containing intact remains, had been recovered, but only four of the victims had been identified.

Divers have been searching through debris on the muddy sea bed for a second black box from the jet, as investigators try to get data from a partly damaged recorder recovered on Thursday.

The pilot of flight JT610 had asked for, and received, permission to turn back to Jakarta but what went wrong remains a mystery.

“Two engines and more landing gear have been found,” Syaugi said.

“I haven’t seen it myself but I got information from some divers that they have seen the fuselage,” he said at a news conference at a Jakarta port where body bags, debris and passenger belongings are first taken.

The sea is only 30 m deep at the crash site but strong currents and nearby pipelines have hampered the search.

Visiting the search operation headquarters at Jakarta’s port on Friday, President Joko Widodo thanked rescue officials and the military involved and appealed for them to step up the search.

-with AAP