The condition of human remains recovered from the crash site of EgyptAir Flight 804 suggests an explosion brought the plane down, a senior Egyptian forensic official told the Associated Press on Tuesday.

The official, who spoke to AP on condition of anonymity, claimed to have personally examined the remains of some of the plane’s 66 passengers and crew at a Cairo morgue. He said that all 80 pieces brought to Cairo so far are small and that “there isn’t even a whole body part, like an arm or a head.”

The official added that “the logical explanation is that it was an explosion”, but “I cannot say what caused the blast.”

Flight 804, an Airbus A320, crashed into the eastern Mediterranean Sea early Thursday morning near the end of a fight from Paris to Cairo. Egyptian authorities said they believe terrorism is a more likely explanation than equipment failure, but no hard evidence of either has emerged.

An independent Cairo daily, al-Watan, quoted an unnamed forensics official in its Tuesday edition as saying the plane blew up in midair but that it has yet to be determined whether the blast was caused by the an explosive device or something else. The official further said the remains retrieved so far are “no larger than the size of a hand.”

France’s aviation accident investigation agency would not comment on anything involving the bodies or say whether any information has surfaced in the investigation to indicate an explosion.

In a search for clues, family members of the victims arrived Tuesday at the Cairo morgue forensics’ department to give DNA samples to help identify the remains of their kin, a security official said. The official also spoke on condition of anonymity because he was not authorized to talk to reporters.

An international effort to hunt for the plane’s cockpit voice and data recorder resumed Tuesday. Ships and planes from Britain, Cyprus, France, Greece and the United States are taking part in the search.

The search area is roughly halfway between Egypt’s coastal city of Alexandria and the Greek island of Crete, where the water is 8,000 to 10,000 feet deep.

The head of Egypt’s state-run provider of air navigation services, Ehab Azmy told The Associated Press Monday that the plane did not swerve or lose altitude before it disappeared off radar, challenging an earlier account by Greece’s defense minister.

Azmy, head of the National Air Navigation Services Company, said that in the minutes before the plane disappeared it was flying at its normal altitude of 37,000 feet, according to the radar reading. “That fact degrades what the Greeks are saying about the aircraft suddenly losing altitude before it vanished from radar,” he added.

“There was no turning to the right or left, and it was fine when it entered Egypt’s FIR (flight information region), which took nearly a minute or two before it disappeared,” Azmy said.

According to Greece’s defense minister Panos Kammenos the plane swerved wildly and dropped to 10,000 feet before it fell off radar.

Greek civil aviation authorities said all appeared fine with the flight until air traffic controllers were to hand it over to their Egyptian counterparts. The pilot did not respond to their calls, and then the plane vanished from radars.

It was not immediately possible to explain the discrepancy between the Greek and Egyptian accounts of the air disaster.

The official website of the Egyptian Aircraft Accident Investigation Directorate, which is affiliated with the Ministry of Civil Aviation, gave details of a 2013 incident in which the plane in question had to make an emergency landing.

It said that the EgyptAir A320 GCC took off from Cairo airport heading to Istanbul at 2:53 and that when it reached an altitude of 24,000 feet the pilot noticed that one engine had overheated. A warning message appeared on the screen reading, “engine number 1 stall.” After checking on best measures to take, the pilot headed back to Cairo airport where a maintenance engineer inspected the engine, disconnected it, and sent it to be repaired.

There were no injuries, no fire, and no damage to the plane, the report read, adding that the engine had a technical problem.

The report is one of over 60 reports classified as incidents, serious incidents and accidents that took place between 2011 and 2014. Among them, 20 involved A320 Airbus planes, the highest among any other aircraft.

Experts contacted by AP said that while an overheated engine is not a common problem, it is unlikely to cause a crash.

David Learmount, a widely respected aviation expert and editor of the authoritative Flightglobal magazine, said, “engine overheat is rare but it happens.”

He said that the pilot can shut down the engine and aircrafts can operate with a single engine.

“I don’t think engine overheat alone has ever caused an aircraft to crash. An engine fire could cause a crash but has not done so in the modern aviation era,” he added.

The Associated Press contributed to this report.