In the fall of 2010, a blogger asked Jane Mayer, a writer with The New Yorker, how she felt about the private investigator who was digging into her background. Ms. Mayer thought the idea was a joke. A few months later, she ran into a former reporter who had been asked about helping with an investigation into another reporter on behalf of two conservative billionaires ... Ms. Mayer recounts in Dark Money: The Hidden History of the Billionaires Behind the Rise of the Radical Right." Her acquaintance told her, "'It occurred to me afterward that the reporter they wanted to investigate might be you.'" Ms. Mayer had published a major story in the magazine that August about the brothers David and Charles Koch, and their role in cultivating the power of the Tea Party movement. [She] began to take the rumored investigation seriously when she heard from her New Yorker editor that she was going to be accused - falsely - of plagiarism. A dossier of her supposed plagiarism had been provided to reporters at The New York Post and The Daily Caller, but the smears collapsed when the writers who were the purported victims made statements saying that it was nonsense. Who was behind this? Ms. Mayer ... traced it to a "boiler room" operation involving several people who have worked closely with Koch business concerns. The private investigation firm ... was Vigilant Resources International, whose founder and chairman, Howard Safir, had been New York City's police commissioner under the former Mayor Rudolph Giuliani.