FILE - This July 2010 file photo provided by the Newtown Bee shows Dawn Lafferty Hochsprung, principal at Sandy Hook Elementary School, who was killed in the shooting inside the school on Dec. 14, 2012, in Newtown, Conn. (AP Photo/Newtown Bee, Eliza Hallabeck, File) MANDATORY CREDIT: NEWTOWN BEE
This image contained in the "Appendix to Report on the Shootings at Sandy Hook Elementary School and 36 Yogananda St., Newtown, Connecticut On December 14, 2012" and released Monday, Nov. 25, 2013, by the Danbury, Conn., State’s Attorney shows ammunition found at Sandy Hook Elementary School in Newtown, Conn. Adam Lanza opened fire inside the school killing 20 first-graders and six educators before killing himself as police arrived. (AP Photo/Office of the Connecticut State's Attorney Judicial District of Danbury)
This image contained in the "Appendix to Report on the Shootings at Sandy Hook Elementary School and 36 Yogananda St., Newtown, Connecticut On December 14, 2012" and released Monday, Nov. 25, 2013, by the Danbury, Conn., State’s Attorney shows a scene outside the entrance to Sandy Hook Elementary School in Newtown, Conn. Adam Lanza opened fire inside the school killing 20 first-graders and six educators before killing himself as police arrived. (AP Photo/Office of the Connecticut State's Attorney Judicial District of Danbury)