veteran federal prosecutor recruit onto special counsel robert mueller team know skill may come handy investigation potential tie russia u.s. president donald trump 2016 campaign team persuade witness turn friends colleagues superiors andrew weissmann head u.s. justice department criminal fraud section join mueller team last month best know two assignments investigation now-defunct energy company enron organize crime case brooklyn new york depend heavily gain witness cooperation secure cooperation people close trump many retain lawyers could important mueller name justice department special counsel may 17 investigate among issue whether trump seek obstruct justice trump deny allegations collusion obstruction flip witness common although always successful tactic criminal prosecutions robert ray succeed kenneth starr independent counsel examine former president bill clinton note trump fire former national security advisor michael flynn already offer lawyer testify congress exchange immunity suggest potential willingness cooperate witness would seem time make decisions leverage apply get things ray say refer mueller team trump vice president mike pence trump son-in-law jar kushner others close president already hire lawyers help navigate mueller expand probe ongoing congressional investigations kathryn ruemmler serve white house counsel former president barack obama say weissmann will take risk secure witness testimony prosecutors might ruemmler work weissmann justice department enron task force investigate massive corporate fraud lead company 2001 collapse ruemmler recall weissmann hunch former enron treasurer ben glisan would will talk despite already plead guilty without agree cooperate weissmann u.s. marshal bring glisan grand jury prison ruemmler say prosecutors might fear glisan testimony could contradict theory case ruemmler say weissmann gamble pay former executive become key witness afraid lose sometimes unusual quality ruemmler say weissmann weissmann also lead lengthy negotiations lawyers andrew fastow enron former chief financial officer star prosecution witness case gain leverage fact prosecutors indict fastow wife also former enron employee tax fraud charge plead guilty fastow testify former enron ceo jeffrey skilling convict 2006. fastow decline comment glisan could reach comment representatives mueller trump legal team decline comment critics say say weissmann hardball approach lead prosecutorial overreach number enron convictions overturn appeal skilling 24-year sentence late reduce 10 years defense lawyer tom kirkendall represent clients relate enron case say task force intimidate witness misinterpret law sam buell former prosecutor member enron task force call criticism routine high-stakes case mueller several highly experience lawyers team include u.s. deputy solicitor general michael dreeben trump also build legal team lead new york lawyer marc kasowitz veteran washington defense lawyer john dowd recently come aboard work relate enron weissmann serve federal prosecutor organize crime bureau brooklyn 1997 trial partner george stamboulidis bring one country powerful mob boss vincent chin gigante help turncoat witness cut teeth organize crime section say stamboulidis private practice way make case get people cooperate even oath omerta mafia code silence non-cooperation authorities strong full play mueller team lawyer bring witness-flipping expertise trump probe