Staff Sgt. Preston Chasteen/U.S. National Guard
Timothy McVeigh and Terry Nichols were convicted in the April 19, 1995, bombing of the Alfred P. Murrah Federal Building in downtown Oklahoma City that killed 168 and injured more than 680 people. McVeigh was executed by lethal injection on June 11, 2001, and Nichols is serving a life sentence with no possibility of parole.