Since last fall, Rep. Waxman has been investigating specific allegations of detainee abuse at Abu Ghraib prison made by a military whistleblower, Sgt. Samuel Provance. After the Pentagon refused to respond to multiple written requests, the Committee agreed on Friday to Rep. Waxman’s request to subpoena Defense Secretary Donald Rumsfeld, compelling him to provide documents about the abuse allegations and reports of retaliation against Sgt. Provance.