Keeler wanted the institute to receive bad publicity  He and Greene were the only ones in a position to tell the press about the institute' s potentially embarrassing affiliations, but Greene had no reason to do so
Ttherefore, it must have been Keeler who notified the press
Carter and Whitequill were the only ones who had any motive to bribe the public official. But Whitequill would have been too fearful that the bribery might somehow be made public. Carter, ttherefore, must be the person who bribed the public official.