In later years, some of assistants criticized his style as being too rigid and old-fashioned and that he may have been in office too long. They cited his prosecution of comedian Lenny Bruce in 1964 and anti-war protestors at Columbia University in 1968. In 1971, Governor Nelson Rockefeller appointed Maurice Nadjari over Hogan and the other New York City district attorneys to lead investigations under the Knapp Commission, which mayor John Lindsay established to investigate police corruption. Chairman Whitman Knapp said that Hogan did not properly investigate corruption in the New York City Police Department leading to Nadjari's appointment. The move left Hogan feeling humiliated and damaged his friendship with Knapp, one of his former assistants.