Michael Cohen spoke to Mueller team for hours; asked about Russia, possible collusion, pardon: Sources originally appeared on abcnews.go.com

President Donald Trump’s former personal attorney, Michael Cohen, has participated over the last month in multiple interview sessions lasting for hours with investigators from the office of special counsel, Robert Mueller, sources tell ABC News.

The special counsel’s questioning of Cohen, one of the president’s closest associates over the past decade, has focused primarily on all aspects of Trump's dealings with Russia -- including financial and business dealings and the investigation into alleged collusion with Russia by the Trump campaign and its surrogates to influence the outcome of the 2016 presidential election, sources familiar with the matter tell ABC News.

Investigators were also interested in knowing, the sources say, whether Trump or any of his associates discussed the possibility of a pardon with Cohen.

Over the 16 months that Mueller has been investigating, the president has repeatedly bashed the investigation as a partisan witch hunt, insisting there has been no collusion and no obstruction of justice.

PHOTO: Michael Cohen leaves Federal court, Aug. 21, 2018, in New York City. (Mary Altaffer/AP, FILE) More

The interviews with Cohen took place in Washington, D.C., and New York City. They were also attended in part by prosecutors from the U.S. Attorney’s Office in the Southern District of New York.

Cohen’s participation in the meetings has been voluntary -- without any guarantee of leniency from prosecutors, according to several people familiar with the situation.

ABC News has also learned that Cohen is also cooperating with a separate probe by New York state authorities into the inner workings of the Trump family charity and the Trump Organization, where Cohen served as an executive vice president and special counsel to Trump for 10 years.

PHOTO: Then-FBI Director Robert Mueller listens as he testifies on Capitol Hill in Washington, June 13, 2012. (J. Scott Applewhite/AP, FILE) More

The news of Cohen’s dealings with federal and state investigators comes close on the heels of another potentially perilous legal development for the president: the guilty pleas last week from Trump’s former campaign chairman, Paul Manafort, who struck a deal with Mueller’s prosecutors in exchange for his cooperation.

As the Manafort deal was taking shape -- Mueller’s team had already been talking to Cohen.

(MORE: Michael Cohen could be key witness in state investigation of Trump charity)

And given Cohen’s prolonged time spent in proximity to Trump, his family and the inner-workings of the Trump Organization, some insiders consider his cooperation with authorities to be one of most serious potential legal threats to confront the president.

PHOTO: President Donald Trump participates in the Sept. 11th Flight 93 Memorial Service, Sept. 11, 2018, in Shanksville, Pa. (Evan Vucci/AP) More

“Both of these guys want to be loved and they both want loyalty,” says a person close to both President Trump and Cohen, who asked not to be named in order to speak freely. “Cohen’s disavowal of Trump has triggered a series of events that turned once very good friends into permanent enemies. The consequences for both will be ugly.”

President Trump and his lawyers have lately been harshly critical of Cohen ever since he made clear earlier this year, in an exclusive interview with ABC News, that he was willing to cooperate with prosecutors, even if that placed the president in legal or political jeopardy. The former Trump loyalist said in the interview he rejected Trump’s claims that the Mueller investigation was a “witch hunt” orchestrated by his political enemies.