Traces of explosives have been found on victims of the EgyptAir plane crash over the Mediterranean in May, investigators say.
A criminal investigation would now begin into the crash of the Airbus A320, Egypt’s civil aviation ministry said in a statement.
Flight MS804 from Paris to Cairo plunged into the sea on 19 May killing all 66 people on board.
The cause of the crash has remained unclear.
No distress call was made beforehand but the cockpit voice recorder revealed the pilots had fought to put out a fire.
Automated electronic messages sent out by the plane showed smoke detectors going off in a toilet and in the avionics area below the cockpit, minutes before the plane vanished.
Recovered wreckage showed signs of damage caused by high temperature and there was soot on the jet’s front section.
Although there were fears that an act of terrorism might have brought the plane down, no group has said it targeted the plane.
On board were 40 Egyptians, including the 10-member crew, and 15 French nationals.
The Egyptian ministry said on Thursday that, under Egyptian law, state prosecutors would take the investigation over “if it becomes clear to the investigative committee that there is criminal suspicion behind the accident”.
In June, the Paris prosecutor opened a manslaughter investigation into the crash.
The French air safety agency BEA and plane manufacturer Airbus both declined to comment on Thursday’s announcement, French news agency AFP reported.
The crash came seven months after a Russian passenger plane was brought down by a bomb over Egypt’s Sinai peninsula, killing all 224 people on board.
An Egyptian affiliate of the Islamic State group said it was behind that attack. However, there was no such claim following the crash in May.