(CBS News) CBS News has uncovered documents that show the State Department may have covered up allegations of illegal and inappropriate behavior within their ranks.

The Diplomatic Security Service, or the DSS, is the State Department's security force, charged with protecting the secretary of state and U.S. ambassadors overseas and with investigating any cases of misconduct on the part of the 70,000 State Department employees worldwide.

CBS News' John Miller reports that according to an internal State Department Inspector General's memo, several recent investigations were influenced, manipulated, or simply called off. The memo obtained by CBS News cited eight specific examples. Among them: allegations that a State Department security official in Beirut "engaged in sexual assaults" on foreign nationals hired as embassy guards and the charge and that members of former Secretary of State Hillary Clinton's security detail "engaged prostitutes while on official trips in foreign countries" -- a problem the report says was "endemic."