Nicole Addimando met Christopher Grover in 2008, when they were coaches at Mr. Todd’s Gymnastics, in Poughkeepsie, New York. At first, they were just friends. Addimando lived with her mother, Belinda, in an apartment complex that Belinda managed. She was nineteen, tiny and delicate, with inky-black hair that fell down her back like a scrim. Her sister described her as shy and introverted. Grover, who was twenty-one, had a gymnast’s build, short and powerfully muscular. People who knew him described him as charming, childlike, and playful, if sometimes short-tempered. He loved video games and had a black belt in tae kwon do. Addimando called him her best friend.