An American citizen fatally shot as he drove through Baghdad on Monday has been identified as 45-year-old Stephen Edward Troell by officials at the Iraqi capital’s U.S. Embassy, according to the Associated Press. Troell was attacked by a pair of “unknown” gunmen as he neared his family’s home in the city’s central Karrada district. He sustained severe injuries and was hospitalized, but later died. Troell, originally hailing from Tennessee, worked at a local English language facility in Baghdad. He was a private citizen with no connection to the government, a State Department source told the AP. No group had claimed responsibility for the killing as of Tuesday evening, and the AP reported that security officials had hand-waved away the theory that it had been a kidnapping gone awry. The rare killing of a foreigner moved Mohammed Shia al-Sudani, Iraq’s new prime minister, to order an investigation into the incident just hours after Troell’s death. “This is a red line for us,” al-Sudani said at a press conference. “Those who want to test our government in terms of security will fail.”