Police investigate an apparent bomb explosion at the Social Security Administration office on Marshall Street in downtown Casa Grande, Ariz. on Friday, Nov. 30, 2012. No one was hurt in

 

              Police investigate an apparent bomb explosion at the Social Security Administration office on Marshall Street in downtown Casa Grande, Ariz. on Friday, Nov. 30, 2012. No one was hurt in
Police investigate an apparent bomb explosion at the Social Security Administration office on Marshall Street in downtown Casa Grande, Ariz. on Friday, Nov. 30, 2012. No one was hurt in the explosion and federal authorities are conducting the investigation. (AP Photo/Casa Grande Dispatch, Steven King)