August 1, 2008: CBS News has reported that Al Qaeda leader Ayman al-Zawahiri may be wounded or dead, based on an intercepted letter acquired by the news organization.CBS News: Exclusive: Al Qaeda No. 2 Injured? (August 1, 2008)U.S. intelligence sources have expressed skepticism toward the report.

CBS received the letter through Pakistani sources, and it believes it was intercepted from Taliban militants.CBS News: Exclusive: Al Qaeda No. 2 Injured? (August 1, 2008) The letter, which requests immediate medical care for Zawahari, is signed by tribal leader Baitullah Mehsud. Zawahiri is thought to be hiding in Taliban-controlled tribal regions of Pakistan.CBS News: Exclusive: Al Qaeda No. 2 Injured? (August 1, 2008)

Pentagon officials have called the CBS report "utterly uncorroborated," while Pakistani Ambassador to the U.S. Husain Haqqani has said that his government is "unable to confirm or deny" reports of Zawahiri's status.CNN.com: No evidence of al Qaeda No. 2's illness or death, U.S. says (August 1, 2008)