Relatives numbed by grief provided samples for DNA tests to help identify victims of the Lion Air plane crash that killed 189 people in Indonesia, as accounts emerged Tuesday of problems on the jet’s previous flight including rapid descents that terrified passengers.

Hundreds of rescue personnel searched seas where the plane crashed, sending more than three dozen body bags to identification experts, while the airline flew dozens of grieving relatives to the country’s capital, Jakarta.

The 2-month-old Boeing 737 MAX 8 jet plunged into the Java Sea early Monday, just 13 minutes after taking off from Jakarta for an island off Sumatra. Its pilot requested clearance to return to the airport 2-3 minutes after takeoff, indicating a problem, though the cause is still uncertain.

Aircraft debris and personal belongings including ID cards, clothing and bags found scattered in the sea were spread out on tarps at a port in north Jakarta and sorted into evidence bags. The chief of the police’s medical unit, Arthur Tampi, said it has received dozens of body parts for identification and is awaiting results of DNA tests, expected to take 4-8 days.

The disaster has reignited concerns about safety in Indonesia’s fast-growing aviation industry, which was recently removed from European Union and U.S. blacklists.

Two passengers on the plane’s previous flight from Bali to Jakarta on Sunday described issues that caused annoyance and alarm.

Alon Soetanto told TVOne the plane dropped suddenly several times in the first few minutes of its flight.

“About three to eight minutes after it took off, I felt like the plane was losing power and unable to rise. That happened several times during the flight,” he said. “We felt like in a roller coaster. Some passengers began to panic and vomit.”

His account is consistent with data from flight-tracking sites that show erratic speed, altitude and direction in the minutes after the jet took off. A similar pattern is also seen in data pinged from Monday’s fatal flight. Safety experts cautioned, however, that the data must be checked for accuracy against the plane’s “black boxes,” which officials are confident will be recovered.

Lion Air president Edward Sirait said there were reports of technical problems with the flight from Bali but they had been resolved in accordance with the plane manufacturer’s procedures. The airline didn’t respond to requests to verify a document purporting to be a Lion Air maintenance report, dated Sunday, that described inaccurate airspeed and altitude readings after takeoff.

In a detailed post online, Indonesian TV presenter Conchita Caroline, who was on Sunday’s flight, said boarding was delayed by more than an hour and when the plane was being towed, a technical problem forced it to return to its parking space.

She said passengers sat in the cabin without air conditioning for at least 30 minutes listening to an “unusual” engine roar, while some children vomited from the overbearing heat, until staff faced with rising anger let them disembark.

After the passengers waited on the tarmac for about 30 minutes, they were told to board again while an engine was checked.

Caroline said she queried a staff member and received a defensive response.

“He just showed me the flight permit that he had signed and he said the problem had been settled,” she said. “He treated me like a passenger full of disturbing dramas even though what I was asking represented friends and confused tourists who didn’t understand Indonesian.”

On Tuesday, distraught family members struggled to comprehend the sudden loss of loved ones in the crash of a new plane with experienced pilots in fine weather.

Many went to a police hospital where authorities asked they provide medical and dental records and samples for DNA testing to help with identification of victims.

Risko, who uses a single name, wept outside the building as he waited with relatives.

“My father was onboard but we still don’t know. We’re still hoping for the best because there hasn’t been an official statement from Lion Air. So we’re still hoping for the best,” he said.

Experts from Boeing Co. were expected to arrive in Jakarta on Wednesday to help with the accident investigation, Indonesia’s National Transportation Safety Committee said. The Transport Ministry has ordered an inspection of all Boeing 737 MAX 8 planes in Indonesia.

Air accident investigator Ony Suryo Wibowo told a news conference that officials have only a small amount of information so far and don’t know if it’s correct. He implored the public to be patient.

“To all Indonesian people, we are saddened and offer condolences but give us time to investigate why the plane crashed,” he said. “Give us a chance to look deeply, to look at the whole problem, so the responsibility given to us by the government can be carried out.”

More than 800 people from multiple agencies are involved in the search, which was expanded Tuesday to a 15 nautical mile area. Specialist ships and remotely operated underwater vehicles have been deployed to search for the plane’s hull and flight recorders.

Search and Rescue Agency chief Muhammad Syaugi said search teams are going “all out” to locate the aircraft’s fuselage.

He has said he’s certain it won’t take long to locate the hull of the aircraft and its flight recorders due to the relatively shallow 30 meter (100 foot) depth of the waters where it crashed.

The crash is the worst airline disaster in Indonesia since an AirAsia flight from Surabaya to Singapore plunged into the sea in December 2014, killing all 162 on board.

Indonesian airlines were barred in 2007 from flying to Europe because of safety concerns, though several were allowed to resume services in the following decade. The ban was completely lifted in June. The U.S. lifted a decadelong ban in 2016.

Lion Air, a discount carrier, is one of Indonesia’s youngest and biggest airlines, flying to dozens of domestic and international destinations. Earlier this year it confirmed a deal to buy 50 new Boeing narrow-body aircraft worth an estimated $6.2 billion. It has been expanding aggressively in Southeast Asia, a fast-growing region of more than 600 million people.