anticipated departure stems from concern that agents of the federal drug agency divulged secrets at sex parties with prostitutes .
colombian drug lords may have staged rendezvous to elicit information .
house committee on oversight and government reform is investigating .
dea declined to comment today on her reported resignation ; the white house would n't give leonhart its backing .
leonhart , head of the agency since 2007 , has been accused by the inspector general of not giving out stiff enough penalties for misconduct .