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