GARLAND, TX - MAY 4: Investigators work a crime scene outside of the Curtis Culwell Center after a shooting occurred the day before May 04, 2015 in Garland, Texas. During the "Muhammad Art Exhibit and Cartoon Contest," an anti-Islam event, on May 03, Elton Simpson of Phoenix, Arizonia and another man opend fire, wounding a security guard . Police officers shot and killed Simpson at teh scene. (Photo by Ben Torres/Getty Images)