Updated at 4 p.m. ET
Editor's note: An earlier version of this report mischaracterized an answer Donald Trump Jr. gave to Senate investigators in 2017 about the prospective projects his family was negotiating with people in Moscow.
The story reported that Trump Jr.'s response — that negotiations on one project concluded by the end of 2014 – contrasted with the version of events as laid out in the guilty plea by Michael Cohen on Thursday. In fact, Trump Jr. and investigators were alluding to a different set of negotiations — not to a deal that Cohen was reportedly pursuing. Trump Jr. did acknowledge in his testimony that Cohen and another man were exploring a possible deal in Moscow in 2015 or 2016.
Trump Jr. did not address what Cohen has now admitted — that talks about such a deal continued at least into June 2016, longer than previously known and well into the presidential campaign.
This week's guilty plea by Donald Trump's ex-attorney Michael Cohen has raised questions about Donald Trump Jr.'s testimony to Congress about his family's real estate negotiations with powerful Russians.
Trump Jr. told the Senate Judiciary Committee in September 2017 that he was only "peripherally aware" about negotiations that Cohen has admitted to carrying on through June 2016.
Cohen said in his guilty plea that he had briefed Trump's family members about his talks, although the court documents don't specify who.
Trump Jr. also told Senate investigators that he wasn't aware that Cohen had reached out to the press secretary for Vladimir Putin as part of his talks with Moscow about a putative new Trump Tower project there.
Cohen had previously told Congress that although he emailed Putin's spokesman, Dmitry Peskov, he hadn't heard back, and the discussions with people in Moscow concluded by January 2016.
Cohen then acknowledged in his guilty plea that, in fact, Peskov had responded to him and he and others had continued negotiations about the project until after Trump had become the presumptive GOP nominee.
Trump Jr.'s answers allude to a number of prospective projects; he was asked by Senate investigators about news reports about a Trump Tower Moscow negotiation that took place in 2015 and 2016, which he acknowledged but did not detail.
An attorney for Trump Jr. didn't immediately respond to a request for comment on this story.
Earlier this year, when other potential discrepancies arose between what Cohen was saying and what Trump Jr. told Congress, attorney Alan Futerfas stood by Trump Jr.'s testimony.
"Donald Trump Jr. has been professional and responsible throughout the Mueller and congressional investigations," he said in the summer. "We are very confident of the accuracy and reliability of the information that has been provided by Mr. Trump Jr., and on his behalf."
Separately, an attorney for President Trump, Rudy Giuliani, said on Thursday that no laws have been broken and that the information that underpins Cohen's plea actually came from the Trump Organization — confirming that it has been supporting the ongoing investigations.
"Michael Cohen is a liar," Giuliani said. "It's no surprise that Cohen lied to Congress. He's a proven liar who is doing everything he can to get out of a long-term prison sentence for serious crimes of bank and tax fraud that had nothing to do with the Trump Organization."
Continued Giuliani: "It is important to understand that documents that the special counsel's office is using to show that Cohen lied to Congress were voluntarily disclosed by the Trump Organization because there was nothing to hide."
President Trump downplayed the importance of the negotiations in a Twitter post on Friday that said he'd only "lightly" looked into a Moscow project and underscored how it never moved forward.
The shift in understanding of the events of 2016 provided by Cohen is important for a few reasons:
First, it called into question the Trump family's denials about having business dealings with Russians. Second, it confirmed the Trumps had a channel open with powerful Russians at the same time the Russian government was waging a widespread campaign of "active measures" against the United States.
And third, it put the Russian government and others in Moscow in the position of being able to know, confidentially, the truth about the Trump family's denials about negotiations over the Moscow real estate deals.
According to Trump Jr. and others who have spoken to Congress, the Trump family negotiated one of its potential projects with Moscow real estate billionaire Aras Agalarov and his family.
Aras and his son Emin also were in the chain of contacts used to convey an offer of help for the Trump campaign from the Russian government to Trump Jr., one that yielded a meeting in New York City in June 2016. Trump Jr. and other top campaign leaders hosted a delegation they believed would deliver dirt on Hillary Clinton.
A representative for the Agalarovs, Ike Kaveladze, also attended that conference on June 9 in New York City. Aras Agalarov asked him to attend, he told Senate investigators. He was briefed beforehand about the presentation he said attorney Natalia Veselnitskaya intended to give, Kaveladze said.
The Russians intended to tell the Trump campaign leaders about what they called a scheme involving American investors funneling money to the Democratic National Committee, Kaveladze told investigators.
The contrasts between Cohen's statement and Trump Jr's version of events may complicate potential legal problems for Trump Jr. Although seldom prosecuted, lying to Congress is against the law — as evidenced by Cohen's plea.
Sen. Richard Burr, R-N.C., chairman of the Senate intelligence committee, said he has made referrals to the office of Justice Department special counsel Robert Mueller because he said he believed people hadn't given his committee the truth.
He declined to identify who might be involved or how often he has referred cases to Mueller, but Burr did allude to Cohen's plea as an example of what he called the consequences that could be involved.
"One instance just highlighted of late is that the special prosecutor made an indictment yesterday using the transcripts of interviews we have done in our committee to indict somebody for lying to Congress," Burr said on Friday.
"It's a loud message to everybody that is interviewed by our committee. ... If you lie to us we're going to go after you."
Trump Jr. was advised in his Senate Judiciary Committee interview that although he hadn't sworn an oath to tell the truth, he was required by law to answer questions from Congress truthfully. He was asked whether he understood that.
"I do," Trump Jr. answered.