Donald Trump is threatening to sue those involved in investigations into his 2016 campaign and presidency, yet again weighing in on a federal criminal case as he thumbs his nose at concerns he is politicizing the Justice Department.

The president also used several Tuesday morning tweets to suggest the case of his convicted friend and former adviser Roger Stone – and any other one stemming from probes of all things Trump – should be "thrown out." The judge in Mr Stone's case, Amy Berman Jackson, has set a Tuesday teleconference hearing with the Stone camp and federal prosecutors to discuss the status of his case.

That set off a firestorm last week when Mr Trump wielded the power of his office post-Senate acquittal in a more muscular way by tweeting that the Justice Department should come down from a planned nine-year sentencing recommendation for Mr Stone on counts of lying to Congress and obstructing justice.

But, in Mr Trump's telling, his longtime friend should soon be a free man.

He called the prosecutors in Mr Stone's case "Mueller prosecutors," referring to the Russia election meddling probe led by former FBI Director Robert S. Mueller III. That investigation concluded with Mr Mueller stopping shy of recommending Mr Trump broke any laws, but saying if wrongdoing had not occured his final report would have said so; it did not. (That final summary also stated Mr Mueller and his team found no direct cooperation between Mr Trump's 2016 campaign and Russians.)

But that did not stop the president on Tuesday morning from contending that "the whole Mueller investigation was illegally set up based on a phony and now fully discredited Fake Dossier, lying and forging documents to the FISA Court, and many other things."

He did not provide supporting evidence as he added his view that the Mueller probe was a "fraudulent investigation" and "badly tainted," calling for it anything related to it to be "thrown out."

"The whole deal was a total SCAM. If I wasn't President, I'd be suing everyone all over the place..." Mr Trump claimed, before adding this threat: "....BUT MAYBE I STILL WILL. WITCH HUNT!"

But Democrats see the situation differently.

"Trump abused his power to coerce Ukraine into announcing investigations for his personal benefit by freezing military aid," House Intelligence Committee Chairman Adam Schiff of California tweeted last week.

Mr Schiff and other Democrats also have panned Attorney General William Barr, who stepped in to back his department away from the nine-year sentencing recommendation after Mr Trump's tweet. (Mr Barr contends he thought there was an internal agreement within the agency to offer Ms Jackson options for a more "flexible" sentence for Mr Stone.)