You can about apply some of this to what's going on with the shooter, as well as all sorts of other people and incidents. Once again, if info (aka "dirt") is not readily available on the intertoobz, there's some deep dark conspiracy in the works.
Na. All the documentation in the world isn't enough for Truthers.
Bart Sibrel, a pseudo famous moon denier, went full loonie and assaulted Buzz Aldrin while calling him a liar and coward, forcing Mr Aldrin to punch Mr Sibrel in the face in order to defend himself.
I could show anyone how steel loses 90% of its structural strength when heated for a minute or two in my forge. And yet 9/11 truthers exist.
Sandy Hook has a bunch of loonies claiming it was... anyone other than a guy with mental issues.
It's not about info, dirt, the truth, human decency, etc. Some people just can't accept reality to be other than what they wish or imagine it to be. To be fair, a lot of such folks have severe mental issues and potentially legit have an inability to determine reality.