First, CNN obtained a recording of a conversation between Cohen and Trump from 2016 discussing how they would buy the rights to a Playboy model's story about an alleged affair.
If true, this bombshell claim by Cohen could bring all sorts of trouble to the president, his son and lawyers who have said Trump did not know of the meeting.
'He can not be believed, ' Rudy Giuliani, a lawyer for Trump, told Reuters on Thursday, referring to Cohen.
"He's been lying all week". "He's been lying all week, or for two weeks - he's been lying for years".
Giuliani added in his Thursday interview that he didn't "see how he [Cohen] has any credibility", referring to Cohen's lawyer's releasing a tape earlier this week of what appeared to be a secretly recorded conversation between Cohen and Trump.
"Donald Trump Jr. has been professional and responsible throughout the Mueller and Congressional investigations", said Alan Futerfas, an attorney for Donald Trump Jr.
"We wouldn't consider it in our best interest to share confidential information with them and they would feel the same way".
Trump Jr. testified before the Senate Judiciary Committee about the meeting, which was also attended by then-Trump campaign chairman Paul Manafort and Trump son-in-law Jared Kushner. The emails, which were later released, show that Trump Jr. was offered documents and information that "would incriminate" Clinton and that the offer was "part of Russian Federation and its government's support for Mr. Trump".
After news of the meeting broke in July 2017, the Trump team offered misleading explanations and changed their story several times.
The man who may hold some of Donald Trump's deepest secrets is up for investigation, in news that will no doubt make the United States leader shiver.
Mueller, who has led the Justice Department's probe into Russian meddling, is also looking into any links between the Russians and the Trump presidential campaign.The probe is also scrutinizing whether Trump sought to obstruct justice by firing Federal Bureau of Investigation director James Comey in 2017 and otherwise undermining other Justice Department officials. "Anything you can think of", the employee said. During the conversation, Cohen can be heard mentioning Weisselberg by name, saying at one point, "I've spoken with Allen Weisselberg about how to set the whole thing up".
President Trump's legal team warned his former lawyer and fixer Michael Cohen, both publicly and privately, that he's in violation of attorney-client privilege and has cautioned him against talking, Trump's lawyer Rudy Giuliani told ABC News.
Trump and his attorneys have said that the recordings had been cut down to make it seem as if the president acted improperly.
Mr Weisselberg has also been linked to the $130,000 hush money payment to adult film actor Stormy Daniels, who claimed she and Mr Trump had an affair in 2006.
Cohen's friends and associates said that as he has fallen deeper into legal trouble this year, the NY lawyer still held onto hope that he would receive Trump's support.
Giuliani's calling Cohen a "pathological liar" would suggest Cohen lied all the time, presumably including when he worked for Trump in the past.
Still, it is so serious that it could theoretically give special counsel Robert Mueller the leverage to propose a deal: Resign the presidency in exchange for immunity for Don Jr.
The subpoena could be a big deal.
Why would it matter if Trump knew about the Trump Tower meeting? .
'There are 12 others, maybe 11 or 12 others out of the 183, in which the president is discussed at any length by Cohen, mostly with reporters, ' Giuliani continued.