Baghdad ? U.S. forces have arrested a deputy of Ahmad Chalabi, who was once the Bush administration’s favorite Iraqi politician, and implicated him in bombings that killed Americans and Iraqis, Chalabi and Iraqi government officials said Thursday.

The U.S. military alleged that the arrested official was working with the “highest echelons” of the Iranian “special groups” criminals, referring to what the U.S. military says are Iranian-backed militias operating in Iraq.

Ali Faisal al-Lami, a Shiite Muslim official and a member of the Sadrist Party who’s serving as an executive of the Justice and Accountability Committee, which Chalabi heads, was arrested Wednesday at Baghdad International Airport as he returned from a family vacation in Lebanon, Iraqi officials said. The Justice and Accountability Committee screens former members of Saddam Hussein’s Baath Party who are applying for jobs in the government.

The American military doesn’t release the names of those it detains. Maj. John C. Hall, a U.S. spokesman in Baghdad said the arrested man was implicated in “multiple criminal acts including bombings and attacks against Iraqi targets” including the bombing June 24 of the Sadr City District Advisory Council meeting, which killed six Iraqis, two American soldiers and two U.S. civilians.