"As a national expert and speaker on mass shootings and gun violence, Dr. Lynn Fenton knew it was impossible to "spot a killer." But when she embarked on treating troubled grad student James Holmes, the hair on her arms stood up. She knew she was dealing with evil. Yet she could find no legal means of locking him up. A decade ago, on July 20, 2012, Holmes struck: he entered a packed movie theater and opened fire, killing twelve people and wounding...