What happens when an author tries so strenuously to empathize with her subject that she loses control of her own book?

It’s a question that kept coming to mind as I read “My War Criminal: Personal Encounters With an Architect of Genocide,” Jessica Stern’s mystifying account of her conversations with Radovan Karadzic, the former Bosnian Serb leader who was convicted in 2016 of war crimes, crimes against humanity and genocide, and is serving a life sentence in prison at The Hague. Stern, a scholar of terrorism and trauma who served on President Bill Clinton’s National Security Council, conducted 12 interviews with Karadzic over the course of two years — making hers the first such study, she says, of a leader tried for war crimes at an international tribunal since the Nazis were evaluated at Nuremberg.

Karadzic was found guilty of orchestrating the massacre at Srebrenica, a Bosnian Muslim town and United Nations-designated safe zone where Serbian forces murdered 8,000 men and boys in 1995, burying them in mass graves. Four years before, he had given a speech to the Bosnian Assembly threatening Muslims with “annihilation” if they voted to secede from the disintegrating Yugoslavia. White supremacists across the world, including mass shooters in Norway and New Zealand, have looked to Karadzic for inspiration.

Stern’s interest in Karadzic isn’t purely academic. As the daughter of a Holocaust survivor, she writes about her “deep curiosity about the causes of evil,” and of a persistent desire to make “creative use of the sequelae of childhood trauma.” Ten years ago, she published a memoir, “Denial,” which recounted in unsparing detail how her grandfather molested her, and how a 15-year-old Stern and her younger sister were raped at gunpoint after a stranger entered their home.