Katharine Lackey

USA TODAY

The man convicted in the shooting rampage at Fort Hood in 2009 that left 13 dead is asking to become a "citizen" of the Islamic State in a letter to the militant group's leader.

Nidal Hasan, 43, the army psychiatrist sentenced to death last year by a military jury, addressed his letter to Abu Bakr al-Baghdadi, who heads the Islamic State, Fox News reported.

"I formally and humbly request to be made a citizen of the Islamic State," Hasan says in the handwritten, two-page document 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's attorney, John Galligan, confirmed the letter to CNN.

"The letter states that Nadal Hasan wants to become a citizen of the Islamic State caliphate," Galligan told CNN. "He wrote it in the last few weeks."

At his trial, the Virginia-born Muslim admitted he was responsible for the Nov. 5, 2009, attack that also wounded 31. He had previously said that he was a "soldier of Allah" and deserved martyrdom, and that his attack was designed to protect Muslim insurgents abroad.