Germanwings crash: What we do and do not know

The co-pilot of the Germanwings flight that crashed into the Alps on Tuesday, killing 150 people, “intended to destroy” the plane, French officials have said.

Here’s what we know:

• Marseille prosecutor Brice Robin, speaking to the press on Thursday, explained: “The intention was to destroy this plane”.

• Citing voice recordings from the cockpit, the prosecutor said the co-pilot, 28-year-old Andreas Lubitz, was alive and alone in the cockpit when the plane crashed.

• Prosecutors said Lubitz manually and "intentionally" set the plane on the descent that drove it into the mountainside in the southern French Alps.

• The pilot had left presumably to go to the lavatory, and then was unable to regain access.

• It is possible to be locked out of the cockpit, as this article explains.

• Robin said after the pilot left the cockpit, Lubitz did not say a word.

• There were a number of appeals from the pilot to be let back into the cockpit which were met with no response.

• They say the most plausible explanation is that the co-pilot refused to let the pilot back in.

• The first 20 minutes of the recorded conversation between the pilot and Lubitz was amicable.

• Carsten Spohr, the chief executive of Lufthansa, Germanwings' parent company told a press conference the airline had no indication of why the co-pilot would have crashed the plane.

• He said pilots undergo yearly medical examination but they do not include psychological tests.

• Sphor said he had confidence in his pilots and were chosen "very carefully".

• He said his airline would not change its procedures immediately as a result of the disaster.

What else has been reported:

• French prosecutors said Lubitz was not known as a terrorist: "There is no element that indicates this is a terrorist action."

• They also refused to call the co-pilot's actions "suicide", saying: "When you are responsible for 150 people, I don't call it that a suicide."

• The pilot has reportedly been identified as Patrick Sonderheimer.

What we do not know:

• The motivation, if any, behind the tragedy.

• If the attack was pre planned.

More: Here's how the Germanwings pilot could have been locked out of the cockpit