"FILE - In this June 23, 2012 file photo, first lady Michelle Obama gives the keynote address to the African Methodist Episcopal Church general conference in Nashville, Tenn. There are conflicting reports about threatening comments a police officer may have made about first lady Michelle Obama, the District of Columbia police chief said Friday, July 13, 2012. The department and the Secret Service are investigating an allegation of what it says were ""inappropriate comments"" about the first lady, allegedly made this week by a city officer who worked as a member of a motor escort for the White House. (AP Photo/Donn Jones)"