AKARTA, Indonesia (AP) — Divers in Indonesia recovered the crashed Lion Air jet’s flight data recorder from the seafloor on Thursday, a crucial development in the investigation into what caused the 2-month-old plane to plunge into the ocean earlier this week, killing 189 people. Relatives, meanwhile, buried the first victim to be identified and prayed at her flower-covered grave.

TV showed footage of two divers after they surfaced, swimming to an inflatable vessel and placing the bright orange device into a large container that was transferred to a search-and-rescue ship.

The Boeing 737 MAX 8 plane crashed early Monday just minutes after takeoff from the Indonesian capital, Jakarta. It was the worst airline disaster in Indonesia in more than two decades and renewed concerns about safety in its fast-growing aviation industry, which was recently removed from European Union and U.S. blacklists.

Navy Col. Monang Sitompul told local TV an object believed to be part of the aircraft’s fuselage was also seen on the seafloor.

The device recovered by divers is the flight data recorder, and the search for the cockpit voice recorder continues, said Bambang Irawan, an investigator with the transport safety committee.

The flight data recorder, or FDR, is expected to provide investigators with detailed information about the flight such as altitude, airspeed and heading. The voice recorder also provides valuable information — not only the cockpit crew’s voices but engine sounds, instrumentation warnings and other audio that investigators can interpret. The U.S. National Transportation Safety Board says sophisticated computer and audio equipment is used to extract and translate the data into an understandable format.

“We will process the data contained in this FDR as part of the investigation process to find out the cause of the crash,” Irawan said. “We cannot say how long it takes to process data in a black box, but of course we will try as soon as possible.”

The flight recorder was recovered from a depth of about 30 meters (98 feet), some 500 meters (1,640 feet) from where the plane lost contact, said search and rescue agency head Muhammad Syaugi.

“The currents below the sea are still strong which makes it difficult for divers, but they persistently faced it,” he said.

Relatives of 24-year-old Jannatun Cintya Dewi, whose remains were identified Wednesday, carried her body in a coffin covered in green cloth along a road in an East Java district to the burial place, followed by dozens of people in a solemn procession.

Her father and others knelt by the grave, which was sprinkled with red, white and yellow flowers, and prayed.

Other families face a longer wait to bury loved ones. Police medical experts say results from DNA tests needed for identification in many cases will take 4-8 days and remains are still being found.

U.S. investigators including from Boeing visited the Jakarta port on Thursday and picked through debris collected from the sea including pieces of aircraft and passenger belongings.

Data from flight-tracking sites show the plane had erratic speed and altitude in the early minutes of a flight on Sunday and on its fatal flight Monday. Safety experts caution, however, that the data must be checked for accuracy against the flight data recorder.

Several passengers on the Sunday flight from Bali to Jakarta have recounted problems that included a long-delayed takeoff for an engine check and terrifying descents in the first 10 minutes in the air.

Lion Air has ordered 50 of the MAX 8 planes and one of its subsidiary airlines was the first to operate the new generation jet last year.

Transport Minister Budi Karya Sumadi said inspections of Boeing MAX 8 planes operated by Lion Air and national carrier Garuda have found no problems but the checks are continuing.

He said the Directorate-General of Air Transportation has asked Lion Air to remove four key officials from duty — its director of maintenance and engineering, quality control manager, flight maintenance manager and release manager — so they can assist the investigation. He said their aircraft maintenance engineer licenses have been suspended.

Investigators say a preliminary report into the accident could be released within a month but complete findings will take several months more.

The Lion Air crash is the worst airline disaster in Indonesia since 1997, when 234 people died on a Garuda flight near Medan. In December 2014, an AirAsia flight from Surabaya to Singapore plunged into the sea, 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. It has been expanding aggressively in Southeast Asia, a fast-growing region of more than 600 million people.