THOROUGH INQUIRY IS PLEDGED BY COX
special Watergate prosecutor A Cox says on May 21 that he will pursue his investigation into Oval Office of White House if trail leads him there, testimony, Sen Judiciary Com hearing on E L Richardson's confirmation as Atty Gen; Sec Richardson says, in response to question on what he would do if Pres asked him for progress rept, that he would refer it to special prosecutor and let him decide; Cox, when asked same question, says he feels he would have absolute right, if 'I felt it were against the interests of the investigation, to refuse'; Sen Byrd announces that he will 'reluctantly' vote for Richardson's confirmation; calls apptmt of Richardson 'regrettable and unfortunate' and says he wishes Nixon had 'gone outside the Adm and brought in a fresh name and a fresh face'; Cox says he will work within guidelines laid down by Richardson; Sen Tunney questions Richardson about his personal friendship with C W Colson, former White House aide who has testified before Watergate grand jury