Meanwhile, federal prosecutors have quietly dropped a criminal probe of the top official overseeing corruption and abuse in the US-led reconstruction of Iraq. Inspector General Stuart Bowen was accused of a series of improprieties, including tampering with employee emails. But critics have said he may have been targeted for political reasons. Bowen’s investigations have indicted several American officials on corruption charges, documented wasteful and inept work by large contractors, and found the Pentagon did not properly track hundreds of thousands of weapons given to Iraqi troops. The Bush administration tried to close down his office in 2006 but backed off following congressional opposition.