Book excerpt: Meet the little known and even less understood heroes of police work in Las Vegas -- the forensic investigators. Led by veteran Gil Grissom, the remarkable team assigned to the Criminalistics Bureau's graveyard shift -- including Catherine Willows, Warrick Brown, Nick Stokes, and Sara Sidle -- must combine cutting-edge scientific methods and old-fashioned savvy as they work to untangle the evidence behind the yellow police tape. While Nick and Catherine investigate a newly discovered fifteen-year-old murder, Grissom and the rest of the team must uncover the indentity of a cold-blooded killer -- one whose execution-style, "double-tap" signature has provoked the interest of FBI agent Rick Culpepper.