A link to what seems to have been a small but overlooked hard evidential trail even Barney Fife should have followed:
http://whatreallyhappened.com/WRHARTICLES/SakherHammad_WTC_9-11.html
There's still no satisfactory answer to "who signed Sakher Hammad's WTC basement work permit" for a couple of days before 9/11 -- Denko Mechanical, the letterhead on the letter presented to the Memphis Court as Hammad's employer approving the WTC work passes, existed only on paper in NY records, tracing back to the Manhattan Apartment of one Sergei Davidenko.
Hammad, when caught by Memphis police in the drivers license fraud scheme, which resulted in the suspicious arson death of Memphis clerk Katherine Smith the day before she was to testify, had the WTC passes in his wallet, and told the police and two FBI agents (who both later took early retirement and have disappeared) that he was working on the sprinkler systems -- which was denied by the Port Authority of New York who had, as law required, a large 24/7 fire safety and sprinkler system contractor -- no one else was allowed to touch the sprinkler system or even any water lines connected to the sprinkler system. This is well established standard fire safety and sprinkler protocol, with which everyone remotely involved with fire safety, sprinkler systems and building security, is familiar. Hammad's explanation could not possibly have been true.
The Memphis reporter who first broke this story is now in the Washington Press Corps. A prominent Memphis defense attorney who represented one of the defendants in the drivers license fraud case, Mr. Robert Friedman, was found shot through the head in a Memphis parking garage in June of 2002. Everyone involved has disappeared except for the judge and, probably, some of the Memphis police involved (I really don't know). All defendants were released.
Something seems wrong here which has never been cleared up or further investigated, by my information. If anyone can find public records or information that explain this incident, I'd be most grateful to learn about it.