As a therapist, Nelba Márquez-Greene has spent a career counseling mentally ill and troubled young people. But she'll never understand what drove a young man to take the life of her 6-year-old daughter and 25 others. A year later, she is trying to prevent violence and promote healing.
More than 60 percent of parents with children in kindergarten through grade 5 reported increased security precautions, according to a recent poll. It was the first national survey since the 1999 Columbine tragedy to ask parents how schools reacted to a mass shooting.