One letter to bin Laden reveals that al Qaeda was working on chemical and biological weapons in Iran.

We have no such weapons at all, no chemical weapons, no biological weapons.

They have involved co-operation between the Iraqi intelligence and al-Qaeda operatives on training and combined operations regarding bomb making and chemical and biological weapons.

When we're talking about technology that involves weapons of mass destruction, nuclear, chemical or biological weapons, there has to be an element of preemption.

In the field of biological weapons, there is almost no prospect of detecting a pathogen until it has been used in an attack.

What surprises me, what amazes me, is that it seems the military people were expecting to stumble on large quantities of gas, chemical weapons and biological weapons.