Where There’s a Will There’s a Murder (Residue Class Mysteries, #2‪)‬

When it looks like an accident, sounds like an accident, and moves like an accident—it's probably a murder. And, when a billion-dollar inheritance is at stake, it's probably lots more than one murder. Time to bring in the Residue Class, a diverse team of amateur sleuths—an international team of mathematal geniuses whose social skills do not equal their skills in mathematics, computers, science, and catching murderers.