Nadal Hasan, the former Army psychiatrist responsible for the shooting at Fort Hood resulting in the death of 13 people, has written a letter to ISIS from prison, asking to become a citizen of the Islamic State’s caliphate.

The letter is two pages long, according to CNN, and addressed to Abu Bakr al-Baghdadi, the leader of ISIS and the self-proclaimed caliph, i.e. religious ruler, over ISIS controlled areas of Iraq and Syria.  The letter is then signed by Hasan alongside the abbreviation SoA which stands for “Soldier of Allah.”

“I formally and humbly request to be made a citizen of the Islamic State,” wrote Hasan, according to 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 was born in America and raised as a Muslim.  He was sentenced to death by a military court for the shooting at Fort Hood in 2009.  Along with the 13 who were killed at Fort Hood, over 30 others were injured during the attack.  According to the Hill, Hasan is currently on death row at Fort Leavenworth, Kan.

Hasan is not the first American to be drawn to ISIS.  Douglas McCain of Minnesota was reportedly killed fighting for the terror group earlier this week.  The Obama administration has said they believe at least 100 Americans have joined and are currently fighting for ISIS.