Ten years passed. I wrote two books and adopted three children from the foster care system, and I kept tabs on the street culture. Then one day in June of 2003, I opened the paper to see a picture of the boy I knew as Highlander. Only now he was twenty-seven, his street name had changed to "Thantos", and he had killed again, this time with another street family. Their victim was a sweet-faced young woman who had a lot in common with my own children: She had been adopted from foster care by a loving family.

I spent the next several years interviewing street youth in prisons, mental hospitals, shelters, and on the street. I crawled through squats on my hands and knees. I collected studies, shelter reports, and statistics. I interviewed police, detectives, investigators, district attorneys, social workers, counselors, anthropologists, sociologists, criminologists, families, and victims— anyone who could lend insight into this unusual, and often terrifying, new criminal society.