Anya was 23, in her final year of college, still living at home while she finished her degree. Her stepbrother Leo had just turned 18 a few months earlier. They had grown up together since she was eleven and he was six, when their parents married. For years they had been close in the easy, uncomplicated way of stepsiblings who actually got along—sharing snacks, fighting over the remote, playing endless rounds of video games and board games on rainy weekends.

That closeness had started to feel different for Anya only recently.