Robert Mueller has fired his first shots at the White House in the Russia investigation, with a former adviser to U.S. President Donald Trump’s campaign admitting he met with purported intermediaries of the Kremlin then lied about it to the FBI, and the campaign’s former chair facing charges over his secret lobbying for allies of Russian President Vladimir Putin.

The indictments, released Monday by the Special Counsel’s office, reveal the strongest evidence so far of ties between Mr. Trump’s circle and the Putin regime that allegedly interfered in last year’s election to help Mr. Trump win. And they put the President’s claims that there was no collusion on increasingly thin ice as the investigation intensifies.

As part of a deal with prosecutors, George Papadopoulos, a foreign-policy adviser to the Trump presidential campaign, pleaded guilty to making false statements to investigators and is now co-operating with Mr. Mueller’s probe. Former chair Paul Manafort and his business associate, Rick Gates, pleaded not guilty to 12 charges that included conspiracy against the United States, failing to register as agents of Kremlin-backed former Ukrainian president Viktor Yanukovych and laundering $75-million (U.S.) in payments through offshore bank accounts.

In the spring and summer of 2016, Mr. Papadopoulos repeatedly met and corresponded with Russian intermediaries in a bid to arrange meetings between campaign officials and Russian politicians, including a prospective meeting between Mr. Trump and Mr. Putin, court filings reveal.

Mr. Papadopoulos and one of his contacts also discussed “dirt” that the Russians had obtained by hacking the e-mails of Hillary Clinton, Mr. Trump’s presidential rival. Earlier this year, U.S. intelligence agencies concluded that the Russian government was behind the release of embarrassing e-mails stolen from the Democratic National Committee and fed to Wikileaks.

Throughout the process, the indictment says, Mr. Papadopoulos frequently updated others in the campaign on his progress.

On March 31, 2016, Mr. Papadopoulos attended a national-security briefing in Washington with Mr. Trump, at which he advised that he could help set up a meeting with Mr. Putin. On another occasion, a “campaign supervisor” told Mr. Papadopoulos he was doing “great work” in trying to connect the Russian leadership and the campaign.

The Trump administration swiftly tried to distance itself from Mr. Papadopoulos and Mr. Manafort, insisting that the Democrats should instead be investigated for trying to dig up Russian-related dirt about Mr. Trump.

“Sorry, but this was years ago, before Paul Manafort was part of the Trump campaign. But why aren’t Crooked Hillary & the Dems the focus?????” Mr. Trump tweeted. “Also, there is NO COLLUSION!”

White House spokeswoman Sarah Huckabee Sanders told reporters that Mr. Papadopoulos had “little role” in the campaign and said the indictments Monday have “nothing to do with the President.” She also vaguely asserted that the White House expected Mr. Mueller’s investigation to end soon, but said Mr. Trump had no plans to fire him.

The indictments suggest Mr. Mueller is far from done.

Solomon Wisenberg, a former federal prosecutor who once worked for the independent counsel that investigated former president Bill Clinton, said the moves send a message to anyone else touched by the investigation: “Be worried, be scared. … We’re serious, we’re not amateurs.” Politically, Mr. Wisenberg said, this also makes it increasingly hard for Mr. Trump to pardon anyone or fire Mr. Mueller.

Mr. Papadopoulos was arrested in July but not charged until this month, raising the question of whether he has been helping the authorities gather information – such as by recording his conversations with other Trump associates – in the interim. “There are a lot of people who are going to have sleepless nights, particularly if they’ve talked to him since July,” said Nick Akerman, a former federal prosecutor who worked on the Watergate scandal.

Mr. Papadopoulos’s Russian connections are unnamed in the indictment, identified only as “the professor,” a “female Russian national” and a man with connections to the Russian foreign ministry. The Washington Post named the professor as Joseph Mifsud, honorary director of the London Academy of Diplomacy.

The prospective meeting between Mr. Trump and Mr. Putin never materialized. One campaign official – unnamed in the indictment but identified by The Washington Post as Mr. Manafort – wrote that Mr. Trump “is not doing these trips.” Mr. Papadopoulos’s higher-ups in the campaign instead encouraged him to make an “off-the-record” trip to Russia himself for meetings with the Kremlin. That trip did not end up happening.

The professor, who was Mr. Papadopoulos’s first point of contact with the Russians, informed him at an April 26, 2016, breakfast meeting in London that Moscow had “thousands” of Ms. Clinton’s e-mails. The meeting bore striking similarities to a June 9 sit-down at Trump Tower between Mr. Manafort, Mr. Trump’s oldest son, Donald Jr., son-in-law Jared Kushner and a Russian lawyer. In arranging the meeting, an intermediary had told the younger Mr. Trump that the Russian government wanted to give the campaign scandalous information about Ms. Clinton.

“I love it,” Donald Jr. wrote in an e-mail at the time. He has subsequently insisted not much of interest happened at the meeting.

Mr. Papadopoulos agreed to a voluntary interview with the FBI in January of this year, at which he falsely insisted his discussions with Russians predated his time on the Trump campaign. He subsequently deleted his Facebook account and changed his telephone number in a bid to hide his communications.

Mr. Manafort worked as an adviser and lobbyist for Mr. Yanukovych and his political party starting in 2006, the indictment against him said, but broke U.S. law by not disclosing to the American government that he was representing a foreign government. He is also accused of failing to disclose his foreign bank accounts or $18-million he brought into the United States, some of which he used to buy properties and take out bank loans against them. When investigators began looking into all this, one of Mr. Manafort’s companies claimed to have deleted e-mails and documents the FBI was looking for.

Monday’s developments are merely opening gambits in the probe. Mr. Mueller will have to decide whether he believes any criminal conduct took place in connection with Russia’s effort to influence the election.

“The special counsel has a witness who is co-operating [and] who has agreed to testify about something that looks to me like collusion between the Trump campaign and the Russian government,” said Samuel Buell, a former federal prosecutor and a law professor at Duke University. “If you’re looking for collusion, you’ve found it.”

Chris Edelson, assistant professor in the department of government at American University in Washington, said the developments in the Russia scandal are all but unprecedented.

“A man on his campaign pleaded guilty to co-operating with the Russians. I’ve never seen anything like this outside of a spy novel. It’s incredible to see,” he said. “I see this as possibly the end of the Trump presidency.”

The Globe and Mail, October 31, 2017