What Specific Reason Was There To Not Put Khalid al-Mihdhar & Nawaf al-Hazmi On CIA Watchlist

From the Joint House Inquiry, panelist, Carl Levin, asks the DCI of CIA, George Tenet, what was the specific reason for not putting two known Al Qaeda terrorists, Khalid al-Mihdhar and Nawaf al-Hazmi, on the CIA's terrorist watchlist.