For those who missed it.
In addition to the actual placement of explosives, those involved would need to clean up any evidence of explosives remaining at the site. In this final essay of a multi-part series, it will be seen that certain people had the means, opportunity and motive to destroy such evidence at Ground Zero, and that something was being hidden after the buildings fell. These facts will be reviewed in light of the knowledge that the debris was considered highly sensitive and nearly all the steel evidence was quickly destroyed.
To read the essay, link here: http://911review.com/articles/ryan/demolition_access_p4.html
To read the first three parts link here.