Less than two years after her 6-year-old son was killed at Sandy Hook Elementary School in 2012, Nicole Hockley was in an Ohio church basement teaching the first class of a program she hoped would help prevent future school shootings. The program, born in the grief of one of the nation’s worst mass shootings, teaches students how to identify warning signs among their peers and urges them to report any red flags to an anonymous tip system or a trusted adult to head off any violence. Since that first class in a Columbus church, the program, “Say Something,” has been presented to thousands of students nationwide. Nearly 395,000 tips have been sent in, ranging from threats of school shootings and suicides to drug use and bullying. One tip last year led to the arrest of an Indiana student who threatened a shooting at her school. “It’s been very successful,” said Hockley, whose son Dylan was among the 20 first graders and six educators who died at Sandy Hook in Newtown, Connecticut, on Dec. 14, 2012.…