FILE - In this May 5, 1995 file photo, thousands of search and rescue crews attend a memorial service in front of the Alfred P. Murrah Federal Building in Oklahoma City. More than 600 people were injured in the April 19, 1995 attack and 168 people were killed. Timothy McVeigh was executed in 2001 and Terry Nichols is serving multiple life sentences on federal and state convictions for their convictions in the bombing. (AP Photo/Bill Waugh, FIle)