Layers of editors and fact checkers:

The shooting happened around 8:20 last Monday morning at the Washington Navy Yard and resulted in the deaths of 12 people.

Alexis had previously claimed to be suffering from PTSD after helping rescue efforts in New York following the 9/11 terror attacks.

It emerged that he used three guns during the massacre, one of them an AR-15 semi-automatic rifle – the same weapon used in the Sandy Hook and Aurora mass shootings.

The FBI confirmed days ago that an AR-15 was never used by the suspect, who was armed with a Remington 870 Express shotgun when he started his attack and who later picked up a pistol from a security guard that was one of his victims.