SUSPECT:A few years ago, journalist Matthew Shaer received a letter from a man who was awaiting trial for a murder he swore he hadn't committed. The most compelling evidence against him? "Touch" DNA — traces of human matter so small and complex that they require algorithmic software to make sense of. Together with fellow reporter Eric Benson, Shaer agreed to look into the case, and the crime that had started it all: a brutal killing at a Seattle Halloween party in which every attendee had been i