Documentary evidence...
...such as the aluminum tubing and other items that it is known they have. What are they using it for?
This type piping is used to enrich uranium (I think) or some other critical step in building things that go "BOOM".
Our hero Scott Ritter says it's just a bunch of pipes.
There are many industrial processes that are, or can be, dual use, benign and malignant.
It is simple to document the design, proposal, order, purchase, receipt, installation, testing, full use and payment of all kinds of things. Easier so when we are talking about multi-million dollar high tech equipment and parts bought from around the world.
I'd be shocked if Hussein hasn't forged a pile of documents by now.
MG, me thinks you are being a bit naive. We're not talking about ballistic finger printing BB guns with the serial numbers filed off.