Ian Rankin's investigation into evil

I highly recommend a YouTube video that is germane to both volumes of That Line of Darkness in which Scottish novelist, Ian Rankin, investigates evil by interviewing a number of experts, including Daniel Pick and Christopher Browning. He begins with a discussion about Robert Louis Stevenson who was a major influence on his own work and proceeds with an analysis of the ideas of Francis Galton, Cesare Lombroso and the serial killer.  He then enters into a discussion with historian, Browning, about how ordinary policemen in the 1940s had a choice about whether to participate in the mass shootings on the Eastern Front. His conclusion, which he links the individual killer with the perpetrators of mass atrocities, should not surprise anybody.

https://www.youtube.com/watch?v=d_RJLQVxN9E