Revealed: Fox News built 400-page dossier on reporter writing book about Roger Ailes

Fox News combed through reporter Gabriel Sherman's real estate records and his Internet history as part of a 400-page "opposition research" document, CNN reported on Friday.

"I don't take it personally," said Sherman, whose 2014 book The Loudest Voice In The Room focused on former CEO Roger Ailes' tactics leading the conservative network. "As I report in my book, Ailes was determined to control his story. This appears to be more evidence of that."

The findings regarding Sherman were distributed in a Jan. 5, 2012 memo titled "to interested parties." It included 41 pages' worth of tweets from Sherman, as well as a New York Times article about his wedding and blog comments about him. It also contained a "hit list" compiling Sherman's reporting on Fox News personalities and GOP "power brokers."

Fox News public relations head Irena Briganti denied the allegations in a statement.

"The Fox News PR department was never involved in conducting or executing any opposition research against Gabe Sherman," she said. "It's been widely reported that there was a separate team not associated with PR which conducted extensive operations unbeknownst to anyone whose official job was to deal with the press."

Earlier this month, Politico reported that Ailes boasted that he could hire someone to "beat the sh*t" out of Sherman, who reported extensively on both the sexual harassment allegations against Ailes and an office Ailes maintained to "spy" on reporters and smear them to the public.