ABC News first reported Thursday that investigators have asked Cohen about any interactions between Mr. Trump and Russia, including business transactions and ones made during the presidential campaign. They have also asked whether Mr. Trump ever discussed a pardon for Cohen, who pleaded guilty last month to eight charges, including campaign finance violations.
A pardon discussion may lead to obstruction of justice charges, along with Russia collusion one of the accusations that Mr. Mueller is probing.
The report also said that Cohen is working with lawyers from Mr. Mueller’s team in New York and Washington and is also cooperating with New York state prosecutors investigating the Trump Organization and Mr. Trump’s charity.
Cohen has not been promised leniency in exchange for cooperation, but it may help reduce his sentence.
The cooperation of Cohen, one of the president’s closest associates over the past decade, would be a coup for the Mueller team. Last week, Mr. Mueller scored another victory when former Trump campaign chairman Paul Manafort pleaded guilty to failing to register as a foreign agent and agreed to cooperate with Mr. Mueller’s investigation.
Their cooperation means Mr. Mueller has two high-level Trump confidants providing his team with information.
Since Cohen pleaded guilty, Mr. Trump and his allies have sought to distance themselves from the man the president once referred to his personal attorney. In May, Rudolph W. Giuliani, Mr. Trump’s current personal attorney, called Cohen, “an honest, honorable lawyer.”
But in July reversed course and accused Cohen of making up stories about the president as part of a lifelong pattern.
“If his back is up the against the wall, he’ll lie like crazy because he’s lied all his life,” Mr. Giuliani told CNN in July.
At a plea hearing last month, Cohen told a federal judge that he arranged hush-money payments for two women who alleged affairs with Mr. Trump more than a decade ago. The president has repeatedly denied the affairs.
But during that same plea hearing, Cohen said the payments were made “in coordination with, and at the direction of a candidate for federal office,” an obvious reference to Mr. Trump. Cohen said the goal of the payments was to keep the affair accusations away from the media.
The money was paid to former Playboy model Karen McDougal and adult film actress Stephanie Clifford, better known as Stormy Daniels. Cohen had previously stated he had paid Ms. Clifford with his own money and without Mr. Trump’s knowledge.