Where is the NSA report on 9/11?

The FBI performed so bad before 9/11 that it took four and a half years to get an unredacted version of the DOJ inspector general's report. The CIA performed so bad before 9/11 that it took nearly six years to get a redacted summary of its inspector general's report. The NSA performed so bad before 9/11 that it has not even admitted its inspector general wrote a report.

Given that the NSA was tapping the hijackers' phones, it surely has a couple of issues to address and explain to the public (for example: why did you let them do it?), but it has not done so as far as I can see. I have never heard of any NSA inspector general report and, when I had a look just now, I couldn't find anything. The NSA admits at its website that it has an inspector general and he is reputed to have begun work on at least one report (into warrantless wiretapping), so presumably he would write a report into the agency's failings before 9/11. However, I can't find a single trace of it. Can anybody help me out here? Is there at least a mention somewhere, anywhere of the NSA inspector general writing a report on the agency's performance before 9/11?

Background on NSA's surveillance of al-Qaeda in general and the hijackers in particular:


Well spotted, please write a

Well spotted, please write a letter or send a fax and publish the correspondence.

Secrecy is anti-democratic.

Where the mind is without fear and the head is held high
Where knowledge is free
Where the world has not been broken up into fragments by narrow domestic walls
Where words come out from the depth of truth
Where tireless striving stretches its arms towards perfection
Where the clear stream of reason has not lost its way into the dreary desert sand of dead habit
Where the mind is led forward into ever widening thought and action
Into that heaven of freedom, let my country awake

— Rabindranath Tagore