(CNN) -- Senior State Department and Diplomatic Security officials may have covered up or stopped investigations of inappropriate or even criminal misconduct by staff, according to an internal memo from the department's Office of the Inspector General.

The timeline surrounding the allegations places the incidents during former Secretary of State Hillary Clinton's tenure, opening the possibility that a widening scandal might taint both her record and her possible political aspirations. Clinton has also taken heat for the department's response to the September 2012 attack on the U.S. Consulate in Benghazi, Libya.

Regarding the latest allegations, CNN was provided the documents by a lawyer for a whistle-blower who is a former senior inspector general investigator.

They include:

• An active U.S. ambassador "routinely ditched his protective security detail in order to solicit sexual favors from both prostitutes and minor children," the memo says. The ambassador's protective detail and others "were well aware of the behavior," the memo asserts. When a diplomatic security officer tried to investigate, undersecretary of state for management Patrick Kennedy allegedly ordered the investigator "not to open a formal investigation."
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