Rescuers load body bags containing debris and body parts onto a rescue ship during the search operations for victims of the crashed Lion Air plane. Picture: PAP Photo/Tatan Syuflan

Jakarta - They came to a police hospital here from all over the country, turning over the most personal belongings of their loved ones - a toothbrush, diplomas, photos - and swabbed their cheeks, providing DNA samples to aid authorities in finding a match with the body parts that continue to be dredged up from the sea.

Families of the 189 victims on the ill-fated Lion Air Flight 610 will now spend their days agonisingly waiting for the inevitable confirmation that their loved ones died in a still-unexplained crash off the coast of the Java Sea, as rescuers continue to search for the plane's fuselage, the black box and bodies submerged among the debris.

On Tuesday morning, the chief of the Indonesian armed forces said the search-and-rescue mission had identified the possible location of the jet's main body, which is likely to hold its black box.

The Lion Air flight, an almost new Boeing 737 Max 8, took off from Jakarta heading to the mining region of Pangkal Pinang on Monday morning, when just a few minutes later its pilot sent an emergency call to the control tower and asked to return. It erratically climbed and fell, its speed gaining dramatically, before losing contact and falling into the sea from an altitude of 3 000 or so feet - what would have been an excruciating and prolonged period of panic for the pilot, crew and passengers on board in their final moments.

Aviation experts and authorities, including the head of Indonesia's National Transportation Safety Committee, told The Washington Post that it is too early to speculate on the cause of the crash. Lion Air has provided information on the aircraft and its maintenance logs to authorities, the chairman of the NTSC said.

The flight data shows that the same aircraft had flown abnormally just a day before, with unusual variations in altitude and speed during takeoff.

Indonesian TV presenter Conchita Caroline, a passenger on that same aircraft which took off from the resort island of Bali Sunday night, said in a post on Instagram that she heard the engine make a weird noise during takeoff that continued throughout the flight. She added that the flight was delayed for more than an hour while a technical issue was being resolved.

Lion Air Group's chief executive, Edward Sirait, said Monday that a prior technical difficulty with the plane was resolved "according to procedure" and that the aircraft was cleared by engineers for take off.

Speaking to reporters Tuesday evening, the airline's director of safety, Daniel Putut Kuncoro Adi, said all the other Boeing 737 Max 8 planes operated by the airline are being inspected.

A team from Boeing is in Indonesia to assist the investigation, he added, and will meet on Tuesday.

As experts attempt to zoom in on what could cause an almost brand-new plane to crash in clear skies, a growing team of rescuers aided by sonar equipment and underwater drones are searching for the wreckage, which could provide crucial clues to what went wrong. Fifty divers have been deployed to the crash site off the coast close to Jakarta, and have expanded the radius of the search, which is expected to last at least a week.

"We hope that by finding the main fuselage, a black box will be found" said Didi Hamzar, the national search-and-rescue agency's director of preparedness, using a common term applied to the cockpit voice recorder and the flight data recorder.

On Tuesday, rescuers were recovering belongings of those on board - passports, children's shoes, identity cards - and officials picked through them to help make identifications. Of those who were aboard the plane, only fragmentary remains have been recovered so far. They are being sent to a police hospital in dozens of body bags, and a forensics team will try to make identifications.

So far, none of the remains have been identified or matched to those who were listed as being aboard the plane.

"None of what we have received is in the form of a full body," said Brigadier General Arthur Tampi, head of the National Police Medical and Health Centre in Jakarta. "So, it is better if a family member does not open [the body bags] because it can cause trauma."

He cautioned that not all the victims will be found. A police officer added that the body parts are "scattered" all over, complicating the DNA identification process.

At the police hospital on Tuesday afternoon, family members filled up stacks of paperwork at the Disaster Victim Identification unit, ascertaining names of the victims and providing details about special markings or tattoos on their bodies. Officials handed out packets of Kentucky Fried Chicken and boxed drinks to the families, many of whom had been waiting at the facility for hours, growing frustrated by the lack of information.

For 64-year old Edi, who like many Indonesians only goes by one name, it was news of his recently-married niece, Amalia "Ayu" Resky, 27, that he was waiting for. He had arrived at the hospital around daybreak, where he went through the motions of filling out the relevant paperwork.

"If they find Ayu's body, we're bringing her back to Palembang. Her mother wants her there," he said, referring to the capital of South Sumatra, the Indonesian region where she was from.

He remembers his surprise when his sister, Ayu's mother, called.

"She seldom calls. So I asked, 'why are you calling me?'" he recalls. "She said, 'did you hear what happened?'"