A US soldier walks between cells with Iraqi detainees at Abu Ghraib prison outside Baghdad. - AFP (File Photo)

WASHINGTON: A secret US federal grand jury is looking into the role of CIA agents in several alleged “war on terror” abuse cases, including the November 2003 homicide of a prisoner at Iraq's notorious Abu Ghraib prison, Time magazine reported Monday.

The dead man, Manadel al-Jamadi, became known as “the Iceman” when his CIA handlers placed his body in ice to slow decomposition in a failed attempt to hide the death.

Prosecutor John Durham has started calling witnesses, including US military personnel who served at Abu Ghraib, before the grand jury investigating the case, the magazine reported.

Durham spokesman Tom Carson had little to say. “This is an ongoing investigation,” Carson told AFP.

US Attorney General Eric Holder appointed Durham in August 2009 to look into several cases of alleged harsh abuse by CIA agents on terror suspects that had been ignored for years.

Durham's grand jury mandate could involve charging CIA officers as well as contract employees in other cases, Time said.

“The grand jury is conducting an investigation of possible violations of federal criminal laws involving War Crimes, Torture and related federal offenses,” the subpoena reads, according to Time.

Al-Jamadi's death at the US-run Abu Ghraib prison was officially classified as a homicide, but the only person ever charged in the case was found to be innocent.

Agents from the Central Intelligence Agency's Inspector General's office sent the case to the Justice Department for possible prosecution, but there has been no movement on the case, Time said.

The magazine first reported on the case in 2005, and ran pictures that included smiling US military personnel posing over the victim's body.