The US Justice Department on Friday charged a captain in Iran's Islamic Revolutionary Guard Corps (IRGC) with killing an American in the Iraqi capital Baghdad in 2022.

The murder and terrorism offenses against Mohammad Reza Nouri, 36, relate to the shooting death of Stephen Troell, 45, who worked at an English language institute in Iraq.

Troell was gunned down in Baghdad on Nov. 7 2022 while driving and accompanied by his wife. His last post on X was a selfie of the couple in Baghdad published June 11, 2018. "How much we loved visiting Baghdad!!! Iraq's treasure is its people," he wrote.

The complaint unsealed in a Manhattan federal court alleged the murder was Iran's retaliation for the killing of top IRGC commander Qassem Soleimani in a US drone strike in Baghdad in 2020.

"The Department of Justice will not tolerate terrorists and authoritarian regimes targeting and murdering Americans anywhere in the world," said Attorney General Merrick Garland in a statement.

"Stephen should still be alive today, and the Justice Department will work relentlessly to ensure accountability for his murder." he added.

Nouri is serving a life sentence in Iraq along with four Iraqis after being convicted there of Troell's murder. He had a played a key role in the targeting and killing of Troell, the complaint reads, including gathering information on Troell and his family.

Nouri is also alleged to have helped procure firearms and a vehicle for the operation. He believed Troell was an American or Israeli intelligence officer, according to the criminal complaint.

Minutes after the attack, he sent an encrypted message to another man involved. "The guys are fine?" he allegedly wrote.