<sod >Congressional Democrats sent a letter to Mr Trump on Friday warning him against using the Nunes memo as a âpretextâ to fire either Deputy Attorney GeneralÂ RodÂ Rosenstein, who is overseeing the investigation, or Special Counsel Robert Mueller who is leading it.< eod>< sod > Taking on this point, Congressional Democrats sent a letter to Mr Trump on Friday warning him against using the Nunes memo as a âpretextâ to fire either Deputy Attorney GeneralÂ RodÂ Rosenstein, who is overseeing the investigation, or Mr Mueller.< eod>