On June 24 and 25, 1975, Nixon gave secret testimony to a grand jury. According to news reports at the time, Nixon answered questions about the -minute tape gap, altering White House tape transcripts turned over to the House Judiciary Committee, using the Internal Revenue Service to harass political enemies, and a $100,000 contribution from billionaire Howard Hughes. Aided by the Public Citizen Litigation Group, the historian Stanley Kutler, who has written several books about Nixon and Watergate and had successfully sued for the 1996 public release of the Nixon White House tapes, sued for release of the transcripts of the Nixon grand jury testimony.