gates was an early subject of independent counsel's investigation, but the investigation of gates intensified in the spring of 1991 as part of a larger inquiry into the iran–contra activities of cia officials. this investigation received an additional impetus in may 1991, when president george h. w. bush nominated gates to be director of central intelligence (dci). the chairman and vice chairman of the united states senate select committee on intelligence (ssci) requested, in a letter to the independent counsel on may 15, 1991, any information that would "significantly bear on the fitness" of gates for the cia post.