Potentially complicating matters, Trump posted a message Friday on Twitter, dismissing the Russia-related probe as a "witch hunt" and lamenting that he's "being investigated for firing the FBI Director by the man who told me to fire the FBI Director!"
The BBC reports that Deputy Attorney General, Rod Rosenstein, wrote a memo the White House used to justify the firing of the ex-FBI chief.
In between tweets about typical presidential fare - jobs, the Army, the state of Wisconsin - President Donald Trump has been ranting in 140-character spurts about the Russian Federation investigation and his former opponent Hillary Clinton. Former House Speaker Newt Gingrich this week called Mueller "now clearly the tip of the deep state spear aimed at destroying or at a minimum undermining and crippling the Trump presidency".
Rosenstein told a congressional panel this week that he was not in favour of firing Mueller without just cause.
"In order to try to attempt to raise a legitimate scenario to fire Mueller, Trump has to discredit him", attorney Jeffrey Jacobovitz, who represented some Clinton-era White House officials, said.
It's the first time Rosenstein has made public comments about the matter. Based in part on the people he is hiring to assist in the probe, some wonder whether he may lean toward a less-than-objective investigation, at the president's expense.
The morning missive appeared to refer to Rod Rosenstein, the deputy attorney general.
But Rosenstein recently informed his colleagues, including Brand, that he might have to recuse himself from the investigation, according to a report by ABC News.
Rosenstein is the only official who could do it because Attorney General Jeff Sessions previously recused himself from the probe into Russian interference in last year's presidential campaign and whether anyone close to Trump colluded with the Russians.
Last day of the Bill Cosby sex assault trial
He co-starred in the 1960s espionage show " I Spy ", the first black performer to star in a weekly American TV dramatic series. Given the manner in which she was dismissed by the previous district attorney, she had no option but to file a civil suit.
Under federal rules, Trump can't fire Mueller.
Any of these alternatives would have the same outcome: decision-making authority over Mueller and the Russian Federation investigation would pass into the hands of the third-ranking official in the Department of Justice, Associate Attorney General Rachel Brand, a former Bush administration official who later served as chief counsel for the US Chamber of Commerce.
Mr Pence's decision to hire Mr Richard Cullen - a veteran of the Iran-contra investigation, Watergate and the 2000 vote recount in Florida - as a private lawyer came less than a month after Mr Trump hired his own private lawyer.
Meanwhile, Vice President Mike Pence has now hired legal counsel to represent him in the Russian Federation probe and there are media reports that the investigation has expanded to include the business dealings of White House adviser and Trump son-in-law Jared Kushner.
Rosenstein sees no reason at this point to recuse himself, the Justice Department said Friday.
Brand is "a horse of a different color from career prosecutors such as Rosenstein, Comey and Mueller", Feldman says.
"Americans should exercise caution before accepting as true any stories attributed to anonymous 'officials, ' particularly when they do not identify the country - let alone the branch of agency of government - with which the alleged sources supposedly are affiliated", Rosenstein's statement said.
'Americans should be be skeptical about anonymous allegations, ' Rosenstein continued. Sad!" Trump tweeted. "Despite the phony Witch Hunt going on in America, the economic & jobs numbers are great. Pence headed the Trump transition until Inauguration Day.
"With this in mind", the memo said, "please immediately suspend any deletion, modification, overwriting, or other possible destruction of the information described above, including electronic information, and take all reasonable measures to preserve this information".


Comments