Trump claims 'business relationship' with Mueller

President Donald Trump, right, has increasingly questioned the credibility of Special Counsel Robert Mueller AFP/SAUL LOEB, Brendan Smialowski

In a series of tweets targeting Mueller's credibility, Trump alleged he had "a very nasty & contentious business relationship" with Mueller.

The message marked the first time Trump publicly elaborated on prior vague claims of conflicts of interest regarding Mueller.

"Is Robert Mueller ever going to release his conflicts of interest with respect to President Trump, including the fact that we had a very nasty & contentious business relationship, I turned him down to head the FBI (one day before appointment as S.C.) & Comey is his close friend," Trump said.

In January, The New York Times reported that Trump had tried to fire Mueller in June 2017 but backed down after White House Counsel Don McGahn threatened to resign if the president made him follow through with the order.

Trump, the Times said, cited three conflicts of interest Mueller had that disqualified him from the high-profile probe.

The alleged conflicts included: A dispute over fees at Trump National Golf Club; work for a law firm that once represented the president's son-in-law Jared Kushner; and an interview for FBI director a day before being named special counsel.

"ILLEGAL SCAM!"

Trump, who has called the probe - which also seeks to determine whether the ex-reality TV star's campaign team colluded with Russia and whether he obstructed justice - a "witch hunt" and repeatedly demanded it be ended, claimed that Mueller's team is filled with Democrats.

Mueller is a Republican like Trump, as is Deputy Attorney General Rod Rosenstein, who hired the special counsel, and Attorney General Jeff Sessions.

In his tweets, Trump also said the investigation was triggered by a damning dossier compiled by former British intelligence agent Christopher Steele, and questioned why Mueller wasn't investigating Democrats.

"There is No Collusion! The Robert Mueller Rigged Witch Hunt, headed now by 17 (increased from 13, including an Obama White House lawyer) Angry Democrats, was started by a fraudulent Dossier, paid for by Crooked Hillary and the DNC. Therefore, the Witch Hunt is an illegal Scam!" Trump said.

"Also, why is Mueller only appointing Angry Dems, some of whom have worked for Crooked Hillary, others, including himself, have worked for Obama....And why isn't Mueller looking at all of the criminal activity & real Russian Collusion on the Democrats side-Podesta, Dossier?"

Mueller's team recently indicted a dozen Russian intelligence agents for hacking into Democratic party computers. Four members of the Trump campaign also have been charged for alleged crimes, but they were not directly linked to collusion.