Complex sentence: Suspicion in Anderson's death falls at first on Leffingwell's loudest supporter, Van Ackerman, and even extends to the President, who vehemently denies to Munson and Hudson knowing about the blackmail.
Split into simpler sentences: Suspicion in Anderson's death falls at first on Van Ackerman, Leffingwell's loudest supporter, and then extends to the President. The President denies to Munson and Hudson knowing about the blackmail.