There's been no shortage of violent crime this decade, either. As the 2010s come to a close, A&E True Crime looks back at the past 10 years—at some of the crime stories that drew the most public attention, and at the criminals the public will long remember.

Dr. Peter Langman, Ph.D, one of the foremost experts in the psychology of school shooting perpetrators, talks to A&E True Crime about who commits these heinous crimes, why they do it and what we can do to prevent the next shooting.