And even though the letter is supposed to be addressed to al-Zarqawi, the last line says, "By God, if by chance you're going to Fallujah, send greetings to Abu Musab al-Zarqawi, " another puzzling inconsistency.

CNN: Al-Zawahiri letter under scrutiny

Eifan al-Issawi was one of the main key founders of a so-called Awakening Council in Fallujah.

BBC: Iraq Sunni MP killed by suicide bomber

Many of the al-Qaida militants escaped to fight another day, and Fallujah was largely destroyed.

NPR: Long-Awaited Fallujah Rebuilding Shows Promise