O.J. Simpson was ordered by the court to give up strands of his hair, so investigators could see if the filaments matched those found in a hat at the crime scene. Although the L.A. District Attorney has officially turned off the tap of information, clues like this one indicating the direction of the investigation continue to dribble out. At the same time, defense attorneys have been aggressively scrambling for evidence to undermine the D.A.'s case. But one "fact" supporting an O.J. alibi seems to have fallen through. Nicole Brown Simpson wasn't talking to her mother on the phone at 11 P.M. the night of the murders -- when O.J. was at home waiting for a limo to the airport. Nicole's father now says the conversation took place at 10 P.M.