MILWAUKEE - Mayor Tom Barrett and some members of the Common Council are asking for the U.S.Attorney's office to investigate the death of a man in the back of a squad car last year. 22 year old Derek Williams was arrested as a robbery suspect by police on July 6, 2011. While in the back of the squad, newly released video shows him telling the officer he couldn't breath. You can also see him struggling to catch his breath. After more than 7 minutes Williams collapsed in the back seat. Despite efforts to save his live, Williams was pronounced dead at the scene. Initially, the Medical Examiner ruled his death related to previous health issues Williams had, but it was changed to homicide after the new information surfaced. The District attorney and the Police Department based much of their findings on the Medical Examiner's report last year. Now investigations have been re-opened and there are calls for The U.S. Attorney to launch a Federal Investigation. Reached by phone Monday, U.S. Attorney James Santelle says he's looking into the matter, but hasn't yet decided whether to begin an investigation.