By Rebecca Shabad - 08/29/14 11:42 AM EDT
The Army psychiatrist who shot and killed 13 people at Fort Hood in 2009 has asked to become a citizen of the Islamic State in Iraq and Syria’s (ISIS) caliphate, according to Fox News.
Nadal Hasan wrote a letter, obtained by Fox, to ISIS leader Abu Bakr al-Baghdadi.
"I formally and humbly request to be made a citizen of the Islamic State," Hasan wrote in the letter, which was two pages and included his signature and the abbreviation “SoA” for Soldier of Allah.
Hasan is an American-born Muslim and former major who was sentenced to death by a military court for a shooting rampage on Nov. 5, 2009. More than 30 people were also injured during the attack. Hasan is currently on military’s death row at Fort Leavenworth, Kan.
He is among a number of U.S. citizens that ISIS and other Islamic extremist groups have attracted.
Obama administration officials say they believe more than 100 Americans have joined these groups overseas and are fighting alongside them. At least two were reportedly killed in a battle in Syria last weekend.