FILE - In this April 20, 2009 file photo, Tom Mauser, father of slain Columbine High School student Daniel Mauser, hugs Lori Haas, mother of Emily Haas, who was wounded in the Virginia

 

              FILE - In this April 20, 2009 file photo, Tom Mauser, father of slain Columbine High School student Daniel Mauser, hugs Lori Haas, mother of Emily Haas, who was wounded in the Virginia
FILE - In this April 20, 2009 file photo, Tom Mauser, father of slain Columbine High School student Daniel Mauser, hugs Lori Haas, mother of Emily Haas, who was wounded in the Virginia Tech shooting, at a Columbine Remembrance and Rededication ceremony at the Capitol building in Denver on the 10th anniversary of the school attack. At far right is Lily Habtu, a Virginia Tech student who was shot three times in the Virginia Tech attack. The year after Columbine, Mauser helped lead an initiative to require background checks for all firearms buyers at state gun shows, a move that didn't prevent accused Aurora shooter James Holmes from acquiring his arsenal. (AP Photo/Chris Schneider)