I must be really dense today, honway. Why would Jayna and Schippers and Reser (possibly the dupe/fallguy) want to shut down the congressional investigation?
Because a shut-down official investigation, or an imperfect one, lets them scream "COVERUP!" and milk this thing for another 20 years. Look at the JFK buffs--there's a whole damn industry out there that caters to them.