The correct answer to this open question is the following.
The President's Commission on Law Enforcement and the Administration of Justice found that gambling was the largest source of revenue for organized crime.
In 1967, Presiden Lyndon B. Jhonson created the President's Commission on Law Enforcement and the Administration of Justice to prevent and combat crime in America. Nineteen people formed this group to study the situation of crime in the United States and proposed ways to diminish criminal activities in the country. The Commission elaborated a full report addressing the situation and it served to reorganize police departments and served as valid arguments to reform legislation.