By Hillary Busis
Updated October 22, 2013 at 02:03 PM EDT

In a new book called Murdoch’s World: The Last of the Old Media Empires, author David Folkenflik — who is an NPR media reporter — writes that in the mid- to late-aughts, Fox’s PR team was tasked with countering “not just negative and even neutral blog postings but the anti-Fox comments beneath them.”

According to a book excerpt posted Sunday on progressive site Media Matters, Folkenflik even found one former Fox staffer who “recalled using 20 different aliases to post pro-Fox rants.”

“Another,” Folkenflik adds, “had one hundred.”

Allegedly, the authors of these fake comments went to great lengths to conceal their true identities. “Several employees had to acquire a cell phone thumb drive to provide a wireless broadband connection that could not be traced back to a Fox News or News Corp account,” Folkenflik explains. “Another used an AOL dial-up connection, even in the age of widespread broadband access, on the rationale it would be harder to pinpoint its origins.”

And the directive to fight criticism with comments apparently came from on high: “Old laptops were distributed for these cyber operations,” according to Murdoch’s World.

Folkenflik cites “four former Fox News employees” as his sources; he does not claim that current staffers are still utilizing these tactics.

Fox News has not yet responded to EW’s request for comment.