BAGHDAD, Iraq (CNN) -- A British security contractor faces charges in an Iraqi court in the killings of two co-workers in Baghdad's Green Zone early Sunday, an Iraqi military spokesman said.
The security firm, ArmorGroup Iraq, identified the dead as Paul McGuigan, a British national; and Darren Hoare, an Australian.
"We are working closely with the Iraqi authorities to investigate the circumstances of their deaths," the company said.
A security source inside the Green Zone identified the suspect as Danny Fitzsimmons, a British national. A second person, also British, was being held for questioning but was released Sunday, the source said.
In addition, an Iraqi was shot twice in the leg during the incident, said Brig. Gen. Qassim Atta, a spokesman for the Iraqi command in Baghdad.
Atta said charges against the contractor in custody have yet to be determined. But the security source said Fitzsimmons would be charged with premeditated murder under Iraqi law. If convicted, he could face the death penalty.
In London, the British Foreign Office confirmed that two Britons were in Iraqi custody in connection with the shooting, but provided no details.
ArmorGroup Iraq provides security to large businesses, international organizations, embassies and non-governmental organizations, according the Web site of its parent company, G4S.
A British Embassy spokesman said the shooting took place inside the company's compound in the Green Zone, the heavily fortified Baghdad area officially known as the International Zone. Iraqi security services are leading the investigation, and the British Embassy is also looking into it, embassy press officer Jawwad Syed said.
The detentions mark the second time Iraq has detained foreign contractors.
In June, five American contractors were detained by Iraqi security forces. Three were released on bond, and the two others were transferred to U.S. military custody.
The five initially were told they were being held in connection with the death in May of another contractor, James Kitterman, according to a source close to the five. Kitterman was found bound, blindfolded and fatally stabbed in a car in the Green Zone on May 22. But later, according to a judicial source, the men were told they were being held on suspicion of having unregistered weapons.
However, Sunday's detentions were the first since contractors lost their immunity under a joint U.S.-Iraqi agreement.
The Green Zone houses the U.S. Embassy and many government ministries.
CNN's Mohammed Tawfeeq, Yousif Bassil and Arwa Damon contributed to this report.
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