The special counsel may have just flipped a key witness in the Russia probe

And Flynn’s cooperation could signal major trouble for Donald Trump and his White House, since Mueller would likely only agreed to a deal with Flynn if he were able to deliver information of great value to the Russia investigation.

Turkish gold trader Reza Zarrab was set to go on trial in a New York City federal court Tuesday for money laundering and conspiracy. Instead, he’s agreed to cooperate with U.S. prosecutors in that case, and speculation is now rampant that he’s also cooperating with Mueller.

The backstory here is a bit thick, and involves key players with ties to the upper echelons of the Turkish government, as well as an ongoing U.S. prosecution of a Turkish banker accused of helping Iran to evade U.S. sanctions.

But if Mueller has indeed secured his cooperation, Zarrab may further illuminate Flynn’s clandestine ties to the Turkish government — which could encourage Flynn to offer up information regarding possible collusion between the Trump campaign and Russia.

The key question Mueller is likely pursuing with Zarrab is this: Did Zarrab discuss with Flynn the reported plot to kidnap a Muslim cleric living in exile in Pennsylvania and return him to Turkey for prosecution?

Flynn and his son, Michael Flynn Jr., were reportedly offered $15 million by the Turkish government to complete the unlikely scheme and deliver Fethullah Gulen to Turkish President Recep Tayyip Erdogan, who has accused Gulen of orchestrating a failed 2016 coup.

According to The Daily Beast, securing Zarrab’s release from the U.S. sanctions case was also part of the $15 million deal Flynn and his son struck with Turkey operatives.

“The meeting allegedly took place at the upscale 21 Club restaurant in New York, just blocks away from Trump Tower, where Flynn was serving on the presidential transition team,” NBC News reported. “Flynn was offered upwards of $15 million, to be paid directly or indirectly, if he could complete the deal, according to two sources familiar with the meeting.”

Incidentally, Flynn wasn’t the only Trump crony tapped to help secure Zarrab’s release; Zarrab also hired Rudy Guiliani to work with the Trump administration and find a “diplomatic solution” to his case — a scheme which did not go well.

Speculation of Zarrab’s flip, which was confirmed in court on Tuesday, first began circulating two weeks ago. Soon after, Flynn’s lawyers ended a joint defense agreement they had with Trump’s attorneys, suggesting Flynn was suddenly cooperating with Mueller’s office.

Flynn’s lawyer reportedly met with members of the Mueller probe on Monday, a further indication that he is pursuing a plea deal.

But if Flynn and his attorney weren’t already trying to cut a deal with Mueller, confirmation of Zarrab’s cooperation might certainly prompt them to do so now.