Ann Rule on the "Stranger Beside" Her.

Ann Rule is a former police officer who became a crime writer. Her new book, Small Sacrifices, documents the case of Diane Downs, who shot three of her children, killing one of them.

In 2003, a hospital nurse named Charlie Cullen was arrested under suspicion of injecting patients with lethal doses of a variety of medications. He is now considered one of the nation's most prolific serial killers. Journalist Charles Graeber explains how the hospital system failed to stop Cullen.

The star of Showtime's bloody crime drama talks about the show's eventual plans for an ending — and also about matters both professional and personal, from how he plays an emotionless killer to how Hall himself, while filming Dexter, has dealt with both cancer and a divorce.