O.J. Simpson and his slain wife's sister traded bitter accusations on live TV yesterday — with Denise Brown calling the disgraced gridiron great a murderer and a "pig." The stunning, impromptu back-and-forth took place when Simpson telephoned Fox News Live while Brown and polygraph expert Edward Gelb were being interviewed about claims that O.J. flunked a lie-detector test following the 1994 murder of his wife, Nicole Brown Simpson. Simpson denied once again that he'd ever taken a test and repeated an offer to take a polygraph for money. "You couldn't pass it to begin with. What makes you think you can pass it now?" Brown said. "You murdered Nicole, and you know you did it." — New York Post