Data from the final moments before EgyptAir flight MS804 crashed into the Mediterranean suggest an "internal explosion" tore through the right side of the aircraft, a pilot said.
Investigators trying to determine whether the A320 was brought down by terrorism or a technical fault are poring over a series of warnings indicating smoke filled the cabin shortly before it disappeared from radar.
French authorities confirmed that smoke detectors went off on board the flight a few minutes before it crashed but said it was not clear what caused the smoke or fire.
A commercial pilot with a major European airline told the Sunday Telegraph that other parts of the data log suggested that windows in the right side of the cockpit were blown out by an explosion inside the aircraft.
"It looks like the right front and side window were blown out, most probably from inside out," said the pilot, who flies an A330 similar to the crashed A320 and spoke on condition of anonymity.
The data was taken from the plane's Acars system, which sends short transmissions from the aircraft to receivers on the ground.
Until investigators find the aircraft's black boxes, which are still missing in the Mediterranean, the Acars offers the best information about what was happening aboard.
Three different warnings showed there were faults in the windows next to the co-pilot, suggesting they could have been blasted outwards by an on board bomb.
That does not mean the explosion came from the cockpit but indicates the right side of the plane was more badly damaged than the left.
The pilot suggested the smoke detectors may have been triggered not by fire but by fog which filled the cabin as it lost air pressure in the moments after the explosion.
Meanwhile, the Egyptian military released images of shoes, handbags and other forlorn items pulled out of the sea near the crash site. Video footage showed unused life vests and torn-up parts of seats scattered across the deck of an Egyptian naval ship.
French and Egyptian ships are focused on trying to recover the black boxes, which would reveal what was said in the cockpit before the plane crashed.
Although no terrorist group has claimed responsibility, French detectives are examining a pool of around 85,000 people with "red badge" security clearance that gives them access to restricted areas of Charles de Gaulle Airport.
The task is complicated by the fact that many work for sub-contractors and turnover is high. Screenings are often limited to checking an employee has no criminal convictions and does not appear on a terror watch list.
Last December around 70 red badges were withdrawn from staff at Charles de Gaulle who were found to have praised the attacks in Paris, prayed at mosques linked to radicalism or shown signs of growing religiosity, such as refusing to shake hands with women.
With no bodies to bury, Egypt continued to mourn the loss of 30 of its citizens but was unable to carry out formal funerals.
Among the dead was a husband and wife who had sold everything to pay for lifesaving cancer treatment and now leave behind their three young children as orphans. Ahmed Ashery, 31, sold his family's flat and car to raise money so his wife Reham could undergo cancer surgery in France, according to the Egyptian newspaper Masrawy.
The couple left their young son and two daughters with his mother and spent a month in Paris, where Ashery had surgery and seemed on the path to a full recovery. They boarded Flight 804 excited to be reunited with their small children.
"Ahmed sold everything to save his wife and ease her grief," said Mohamed al-Shenawi, a family friend. "I advised him to accept the command of God and look for treatment in Egypt but he insisted on travelling."
Family and friends of flight attendant Yara Hany Farag gathered at a Coptic church in Cairo to grieve around a cross of white flowers with a picture of the young woman. Her grandmother stood in front of the picture crying: "Yara answer me, I want hold you."
Her mother described her unmarried daughter as "a bride for heaven".
Earlier in the day the family were asked by EgyptAir to provide DNA samples to help with identification of bodies. So far a few human parts but no full bodies have been recovered.
In a dark premonition of things to come, it emerged that the crashed aircraft had once had graffiti written on it: "We will bring this plane down".
The New York Times reported that the vandalism was done two years ago and was a protest against Abdel-fattah al-Sisi, the Egyptian President who seized power in a coup, rather than a jihadist threat.
The airline went on to fire a number of staff with alleged Muslim Brotherhood sympathies in 2013 as part of a general purge of suspected Islamists after the military takeover.
In the weeks after the Paris attacks in November, French police said Arabic graffiti such as "Allahu Akbar" (God is great) were found daubed on EasyJet and Vueling planes at Charles de Gaulle airport in Paris and at Lyon airport.
The discoveries raised fears that a bomb could be planted on a plane at an airport in France, but Easyjet and the French authorities insisted there was nothing to worry about.