By Paul Reynolds
World Affairs Correspondent, BBC News website
Security camera image of attack on Pentagon
The release of new video pictures of the Pentagon being attacked on 9/11 will not quell the endless claims in the world of conspiracy theorists that a missile or military aircraft hit the building instead.
The theorists do not believe eyewitnesses, physical evidence, engineering studies or even the claims of Osama Bin Laden, so it is unlikely that they will be convinced by grainy video frames.
The latest pictures are the missing frames from a series taken from two cameras at a filling station.
If you look closely, you do see what could be a plane, flying very low and then hitting the building, causing a huge fireball. It is consistent with the official account.
However, the new frames do not absolutely without doubt show that this was American Airlines 77 in its final moments, so hope will spring eternal for the conspiracists that they have not been knocked out.
And even if the pictures did clearly show the doomed airliner, the theorists would probably just change their charge.
After all, in the case of the Twin Towers, they argued that the attacks were carried out by, or tolerated by, the US government. The Pentagon could easily be fitted into that category as well.
To understand the conspiracy theory, it is worth considering a film called Loose Change: 2nd edition. Available on the internet, it reveals the full alternative version of what happened to the Pentagon in all its glory. It states:
AA77 did not crash into the building. And if there was no AA77, it must have been a missile, a military aircraft or a drone that did it
The alleged pilot Hani Hanjour was not skilled enough to execute the manoeuvre and the plane would have stalled in the tight turn alleged
Street lights were knocked down but did not bring down the plane; therefore there was no plane. They could have been deliberately lifted from the ground
The damage was not consistent with the size of the airliner and therefore there was no airliner
There were no remains of either the 757 or passengers and therefore neither existed
- Pieces of fuselage found nearby were planted
Eyewitnesses who said they saw the plane were confused. Others said they saw a commuter jet or a helicopter
There are, of course, answers to all of the above, to be found in the report of the 9/11 Commission, in other technical assessments and in common sense.
For example, the limited damage on each side of the impact zone was due to recent strengthening work on the building. Windows that survived were made of shatterproof glass.
Another obvious weakness in the film is that the eyewitnesses chosen are all treated as if they have equal value. And did nobody see the lampposts being lifted out of the ground?
And the passengers...?
The most glaring gap in the theory is surely this. If AA77 did not end its flight hitting the Pentagon, what happened to it and its passengers?
This appears to be of little relevance to 9/11 theorists. In the course of an e-mail exchange with one of them I asked this question and was told that for all she knew, the plane could have been diverted somewhere and the passengers gassed.
One of the passengers was well-known. She was Barbara Olson, wife of Ted Olson, the US Solicitor general. However, I was told by the theorist that two calls she made to her husband from the plane probably never existed. Exactly where she might be now remains a mystery, it seems.
The film "Loose Change" also claims incidentally that United 93 which came down in a field in Pennsylvania, never crashed (the "crash site" was dug out by bulldozers) but landed at Cleveland and the passengers taken off. What happened to them, one wonders.
It also says that the Twin Towers were brought down by "controlled demolition". Again, great emphasis is placed on immediate eyewitness accounts of "explosions" within the towers, and almost none on later engineering examinations of the sequence of the collapse.
Plane comes into view at far right
The film is the work of three young American videomakers, who started off making a fictional film about how they revealed that 9/11 was a US government conspiracy.
One of them, Dylan Avery, has described what happened next: "It was that month that I began writing Loose Change, a fictional story about my friends and I discovering that 11 September was not a terrorist attack, but rather, an attack by their own government.
"Upon researching for the movie, it became apparent that the subject matter might not have been entirely fiction. Over two years time, adding more and more information, the fictional movie evolved into what it is today: a documentary."
The film is quite professionally done on a technical level, with sinister music and fast cutting. Avery said it cost only $2,000 to make and was done on a laptop.
It is proving popular on the internet in reinforcing beliefs that 9/11 might not have been all it seems.
The theorists are very small in number but are working in fertile soil. The events are endlessly fascinating.
And the fact remains that some people around the world believe that somehow the US government might have been involved.
Part, most probably, of that suspicion has to do with anger against the United States. There are always conspiracy theories involving the US right across the Middle East and beyond. Many people want to believe the worst.
The new pictures will not have much effect on that kind of thinking.
It might well be that, as in the case of the Kennedy assassination, it will take many years for the theories about a US government conspiracy on 11 September 2001 to fade.