Nidal Hasan, the Army psychiatrist who was convicted of murdering 13 people in the 2009 shooting at Fort Hood, has written a letter to ISIS leader Abu Bakr al-Baghdadi requesting his acceptance into the group's self-declared caliphate. "I formally and humbly request to be made a citizen of the Islamic State," Hasan apparently wrote in the letter, first obtained by Fox News.

"It would be an honor for any believer to be an obedient citizen soldier to a people and its leader who don't compromise the religion of All-Mighty Allah to get along with the disbelievers," Hasan writes. From Fox News:

Hasan's attorney, John Galligan, said the letter "underscores how much of his life, actions and mental thought process are driven by religious zeal. And it also reinforces my belief that the military judge committed reversible error by prohibiting Major Hasan from both testifying and arguing…how his religious beliefs" motivated his actions during the shooting.

According to Fox News, the two-page, handwritten letter is signed "SoA," for "Soldier of Allah." Hasan was sentenced to death by lethal injection exactly one year ago for the killings at Fort Hood.

[Image via AP]