[BBC] – Traces of explosives have been found on victims of the EgyptAir plane crash over the Mediterranean in May, investigators say.

A statement by Egypt’s civil aviation ministry said a criminal investigation would now begin into the crash of the Airbus A320. 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 may have brought the plane down, no group has said it was responsible. The Egyptian ministry said on Thursday that, under Egyptian law, prosecutors would take the investigation over “if it becomes clear to the investigative committee that there is criminal suspicion behind the accident”.

Those on board were 40 Egyptians, including the 10-member crew, and 15 French nationals.