NEW YORK: More than ten years after he described being beaten by a mysterious man shouting, "Kenneth, what's the frequency?" Dan Rather has finally identified his assailant. Rather said Tuesday that "there's no doubt in my mind" that William Tager, now in prison for the 1994 shooting death of an NBC technician, is the man who repeatedly kicked him while he was walking down Park Avenue in the fall of 1986. Rather was tipped off to Tager's identity by a psychiatrist who interviewed Tager after he was arrested for shooting Campbell Theron Montgomery. Montgomery was killed when he alerted police to Tager, who was attempting to enter the show's ground-floor studios with an assault rifle. Both attacks were apparently fueled by Tager's belief that the media was after him. By demanding "the frequency" from Rather, Tager was trying to find a way to stop the media from beaming hostile messages into his brain. Although initially embarrassed and hostile in answering questions about the incident, Rather began to view the story with humor as it receded into the past. He even went so far as to appear on stage with the rock group R.E.M. two years ago to help sing its song, "What's The Frequency Kenneth?" To some, his off-key performance was conclusive proof that the media is indeed beaming hostile messages at people.