Are you a serial killer? If so, you should fear Thomas Hargrove. Or at least his algorithm. “On Aug. 18, 2010, a police lieutenant in Gary, Ind., received an e-mail, the subject line of which would be right at home in the first few scenes of a David Fincher movie: ‘Could there be a serial killer active in the Gary area?’” Let Bloomberg introduce you to the man who is “building software to identify trends in unsolved murders using data nobody’s bothered with before.”