Fox News says it has fired an associate producer after learning he was the "Fox Mole" hired by the news blog Gawker.
The network says Joe Muto was let go, effective Thursday.
The associate producer of "The O'Reilly Factor" made his debut as an anonymous columnist on Gawker on Tuesday. He was hired to provide regular posts from inside the network.
Fox said in a statement Muto was fired after it determined he "was the main culprit in less than 24 hours."
The network said it "was continuing to explore legal recourse against Mr. Muto and possibly others."
Muto's inaugural post included a previously unseen video of Republican presidential candidate Mitt Romney chatting with Sean Hannity, discussing his family's horses, among other things.
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