Trump's digital volley appeared to be trained at Deputy Attorney General Rod Rosenstein, who recommended the firing last month of James Comey - an nearly unprecedented move that could yet imperil Trump's presidency.
Mueller, a former FBI director who was named special counsel for the Russian Federation investigation after Comey was sacked, is investigating whether the Trump campaign colluded with Kremlin officials in a bid to tilt the 2016 election in his favour.
But as the legal rope has tightened, Trump's allies have gone on the offensive, questioning the credibility of the special investigator Mueller, a respected former Federal Bureau of Investigation director who served under Republican president George W. Bush. Mueller was appointed by Deputy Attorney General Rod Rosenstein and has expansive powers to probe any matters that develop from his initial investigation. Those associates include former national security adviser Michael Flynn, campaign chairman Paul Manafort, foreign policy aide Carter Page and outside adviser Roger Stone.
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.
This week's set of controversies, including reports that President Trump was considering firing special counsel Robert Mueller, has led to an increase (again) in speculation that it won't be long until Trump is either forced to resign or undergo impeachment proceedings that will surely see his ouster from the Oval Office.
The poll also found there is a growing concern over the possibility that Trump's campaign colluded with Russian operatives during last year's election.
The tweet on Friday was the first official confirmation by Trump that he himself is under investigation. Rosenstein, who would be responsible for actually dismissing Mueller, told U.S. lawmakers he would fire him only with good cause. Rosenstein, who would be responsible for actually dismissing Mueller, told USA lawmakers he would fire him only with good cause.
Trump is under pressure to reveal whether he has any tape recordings of private conversations with Comey. Rep.
Dowd, 76, joins longtime Trump lawyer Marc Kasowitz; Jay Sekulow, the TV face of the team, who's doing a "full Ginsburg" blitz oftomorrow's Sunday shows; and Mark Corallo, a Justice Department alumnus who was Rep.
If Trump's goal is to limit Mueller's probe or force him out, Republican Senator John McCain of Arizona said this week, "that would be disastrous for him".