Jan Jürgen (John) Petersen was a charismatic man who some thought of as a spiritual guru. Petersen’s charm helped him survive the five-year Nazi occupation of the Netherlands. But beneath his genial exterior was a darker side. He served in the Dutch SS but was also a member of the Schutzgruppe, a semi-military organization attached to the German army. He played these organizations against each other, assisting both the Germans and the Dutch resistance, contributing to some horrors, includi...