Last year I published This House of Grief, a book about the trials of a Victorian man, Robert Farquharson, who was found guilty of drowning his three young sons in revenge against his former wife. When the book came out I was struck by the number of interviewers whose opening question was “What made you interested in this case?” It always sounded to me like a coded reproach: “Is there something weird or peculiar about you, that you would spend seven years thinking about a story like this?”