So far no evidence has been found of a security breach at Paris's Charles de Gaulle Airport. But that hasn't stopped French authorities launching an investigation.
This is the largest airport in France. The second busiest in Europe. Security here is extremely high.
Even more so after the November terror attacks when security was tightened with police and army patrols increased and video surveillance strengthened.
Aviation experts say, with some of the strictest measures in the world, a security breach here would be extremely unlikely.
But French authorities are not taking any chances.
All employees of the airport and the airline that could have had access to the plane or luggage prior to take-off have reportedly being questioned.
It's important to note that there is currently no specific information pointing to a security breach here at Charles de Gaulle.
And the doomed plane had also been at Asmara, Tunis and Cairo airports during the 24 hours before landing in Paris.
Even so there have been rising concerns over the past year about the potential security risks among the CDG staff.
Last year a number of baggage handlers and other airport staff were suspended or lost their jobs because they were suspected of links to radical Islam.
And people here are acutely aware of the ongoing terror threat.
On Thursday the head of France's internal intelligence agency said so-called Islamic State militants are gearing up for a campaign of bomb attacks during next months Euro 2016 football championships, which are being held here in France.