– Robert Mueller has for the first time publicly connected Donald Trump’s presidential campaign and business to the Russian government, adding a significant new chapter to the special counsel’s ongoing investigation into Russian efforts to interfere in the 2016 elections.

In a guilty plea Thursday, Trump’s former lawyer and fixer Michael Cohen admitted that he spoke with Trump and Russian officials as late as June 2016 — a month before Trump officially accepted the Republican presidential nomination — about a potential business deal in Moscow that Cohen told Congress had ended months earlier.

Here are the key takeaways from Cohen’s plea for lying to Congress:

Ties Trump to Russia during the campaign

Mueller’s “criminal information” filing lays out multiple exchanges between Cohen, real estate developer Felix Sater and Russian government officials about a proposed Trump tower development in Moscow.

While the deal never went through, conversations about it between Cohen, Trump, his family and at least one campaign official came as Russia was in the midst of a sophisticated plan to interfere in the U.S. election.

“This is enormous,” said Mimi Rocah, a former federal prosecutor. “We’re seeing financial motives and financial entanglements with a foreign power who interfered in our elections.”

Cohen discussed the Moscow tower project with Trump at least four times, including the possibility that the presidential candidate would travel to Russia, according to the filing. Cohen also briefed Trump family members about it and discussed the possible travel with a senior campaign official.

Cohen had told House and Senate intelligence panels in August 2017 that all talk of the Moscow project ended in January 2016, before any of the caucuses or primaries. He said he made the false statement to help Trump and limit the ongoing Russia probes.

Doesn’t prove collusion or conspiracy by itself

It’s not illegal for a presidential candidate to simultaneously explore possible business deals overseas, as Trump emphasized to reporters on Thursday. But the ongoing contacts raise continuing questions about Trump’s attitude and motivations toward Russia.

Adds to list of Russian contacts

About the time Cohen was in contact with Russian officials and discussing a possible Russia trip for Trump, campaign foreign policy adviser George Papadopoulos was doing the same.

A Russian contact e-mailed Papadopoulos saying his country was “open for cooperation” and offering to arrange a meeting in Moscow. Several weeks later, Papadopoulos e-mailed a senior campaign staffer trying to set up a Trump trip to Moscow, writing, “Russia has been eager to meet Mr. Trump for quite sometime.”

On June 9, a Russian lawyer visited Trump Tower in New York for a now infamous meeting with Trump’s son Donald Trump Jr., son-in-law Jared Kushner, and campaign chairman Paul Manafort.

In early July, another Trump campaign adviser, Carter Page, traveled to Moscow, where he gave a commencement speech and says he briefly interacted with Deputy Prime Minister Arkady Dvorkovich and had a meeting with Andrey Baranov, head of investor relations for oil giant Rosneft.

Gives an opening into Trump’s business

Trump has previously said that Mueller would be crossing a red line if he looked into his business dealings. But Cohen’s guilty plea could contribute to the special counsel’s rationale for delving more deeply into the Trump Organization.

E-mails cited in the plea deal came from the Trump Organization, which turned them over to prosecutors.

Rudy Giuliani, Trump’s attorney, said the documents Mueller’s office “is using to show that Cohen lied to Congress were voluntarily disclosed by the Trump Organization because there was nothing to hide.” He also called Cohen 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.”

It’s significant that Mueller negotiated the plea agreement with Cohen, rather than having another U.S. Attorney’s Office do so, as happened with the charges brought against Cohen earlier this year related to hush-money payments to adult performer Stormy Daniels, Rocah said. It’s a strong indication that Cohen’s lies, as well as other information Mueller may have, is directly relevant to his investigation into whether Trump or any of his associates conspired with Russia.

“The walls are crumbling down on top of them from so many different directions,” Rocah said.

Contradicts Trump’s past statements

Trump has repeatedly denied having business ties to Russia during the presidential campaign and as president. While those statements appear to be accurate in regard to the Moscow tower project that never came to fruition, he appears to have been downplaying his business relationship.

He tweeted in July 2016 — just a month after it’s now known that discussion on the Moscow development stopped — that he had “ZERO investments in Russia” and that accusations of “Russia dealing with Trump” were “crazy.”

At a February 2017 news conference at the White House, he expanded on that assertion, saying, “I have nothing to do with Russia. To the best of my knowledge no person that I deal with does.”

Underscores that guilty pleas keep growing

Rep. Jerrold Nadler, who’s in line to head the Judiciary Committee when Democrats take control of the House in January, said Thursday that the list of Mueller successes was long and damning.

“The special counsel has now secured guilty pleas from President Trump’s personal attorney, his campaign manager, his deputy campaign manager, a foreign policy adviser to his campaign, and his national security adviser,” Nadler said in a statement. “The president can pretend that this investigation has nothing to do with him and nothing to do with Russia, but these indictments speak for themselves.”