The endgame is approaching in Robert Mueller’s investigation into Russian interference in the US presidential election and the latest news to emerge shows that the person with the legal codename “Individual 1” is very much at the centre of scrutiny.

This is bad news indeed for Donald Trump, “Individual 1.” He, of course, has been attempting to dismiss the inquiry, mainly through tweets and with increasing shrillness, as “fake”, a “fraud” and a “witch hunt” that will end up finding nothing incriminating.

But as the indictments by the special counsel mounted up – against 32 people at the last count – the president’s more realistic supporters had been presenting the scenario that although people around him may get burned, he himself will survive.

The view was echoed by John Bolton, now Mr Trump’s national security advisor, when I discussed the matter with him at a conference in the Ukrainian capital, Kiev, a while ago. One of his predecessors in the post, Michael Flynn, may have pleaded guilty, Mr Trump’s campaign manager, Paul Manafort may have been charged, but the president himself, felt Mr Bolton, will remain untouched.

It is someone far closer to Mr Trump than former Lieutenant General Flynn and Mr Manafort who now poses the most peril for the president – Michael Cohen, his personal lawyer, confidant and fixer for years, the man who kept the secrets and, prosecutors believe, know where skeletons are rattling away about the president, his family and close associates.

Mr Mueller, after sticking to protocol and not making major legal moves in the lead up to the midterm elections (even though Mr Trump kept up a steady barrage of insults towards him during that time) came up with one of the most significant successes of his investigation, with Mr Cohen becoming the first person in the case to plead guilty of lying to congressional investigators.

The primary focus of investigations into Mr Cohen until now has been from the New York district attorney’s office involving allegations of tax and campaign finance misconduct, which in itself was problematic for Mr Trump. But with his latest admission of guilt, the president’s former personal lawyer moves directly into the orbit of Mr Mueller’s investigation.

There has long been a belief among those who have been observing the investigations into the president – by the special counsel and the House and Senate intelligence committees – that the problem for Mr Trump is the examination of his business dealings. That “they will get him on the money at the end, like they got Al Capone”, was one of the adages doing the rounds.

Mr Cohen is now giving information to the Mueller inquiry into the Trump Organisation’s business interests in Russia during the run-up to the US presidential election, in particular plans to build a Trump Tower Hotel in Moscow.

The lawyer had previously claimed that the Moscow project ended in January 2016, before Mr Trump’s campaign could be said to have got under way. In a New York courtroom on Thursday, he now admits: “I made these statements to be consistent with Individual 1’s political messaging and out of loyalty to Individual 1”.

Asked about the Russian business interest revelations as he was flying off to the G20 summit in Buenos Aires, the president accused Mr Cohen of being a “weak person” who is “not very intelligent”. In July 2016 Mr Trump had tweeted “For the record, I have ZERO investments in Russia”, a day later he wanted to clarify that “I have nothing to do with Russia”. In January 2017 he insisted, “I have no deals that can happen in Russia, because we have stayed away.”

But following the latest Cohen revelations this has now become: “There would have been nothing wrong if I did do it. When I am running for president, that doesn’t mean I’m not allowed to do business.”

Adam Schiff, who will chair the House Intelligence Committee after the Democrats gained control of the House of Representatives, wanted to stress: “If Mr Cohen misled the congress about the president’s business dealings in Russia deep into the campaign, it also means that the president misled the country about his business dealings and that the Russians were apparently attempting to gain financial leverage over the potential president of the United States.”

The information provided by Mr Cohen, who is said to have spent more than 70 hours with the special counsel’s team, is just one source of problems for Mr Trump. A document from Mr Mueller’s office showed a close interest in the president’s dealings with Roger Stone, a long-term friend and advisor at a time when Mr Stone is said to have been seeking to liaise with WikiLeaks over the release of hacked Democratic Party emails.

Jerome Corsi, another Trump ally, had allegedly told Mr Stone – “Person 1” in the legal code of the document – about the WikiLeaks plans to make the emails public in October 2016 because he knew that Mr Stone was in “regular contact” with Mr Trump.

Mr Stone allegedly asked Mr Corsi to reach out to Julian Assange, the WikiLeaks founder who had been living at the Ecuadorean embassy in London to avoid being extradited to Sweden on sex assault charges, days after it had released hacked Democratic National Committee emails. The aim was to coordinate tactics.

Mr Stone and Mr Trump, it has been claimed, spoke together the day after Mr Corsi sent his message. Mr Trump, in written answers to questions sent by Mr Mueller (after the president’s lawyers persuaded him not to be interviewed personally by the special counsel’s team because of the risk that he may perjure himself) has denied speaking to Mr Stone about the hacked emails.

Lawyer Alan Dershowitz: Mueller report to be 'devastating' for Donald Trump

Mr Trump had also denied in his written response to Mr Mueller that he knew about a meeting between his son, Donald Jr, his son-in-law, Jared Kushner, and Paul Manafort with a group of Russians, including a lawyer who claimed to have incriminating materials about Hillary Clinton.

The special council’s team is believed to be examining claims that Mr Trump knew about the meeting and subsequently helped in the drafting of his son’s response about the meeting to the investigations. Mr Schiff has said he wants to get details about the telephone call Donald Jr made during the talks with the Russians.

Meanwhile it has emerged that the legal teams of Mr Trump and Mr Corsi may have agreed to a mutual defence agreement in relation to the special counsel’s investigation. Mr Corsi has acknowledged that his lawyer, David Gray, has been in contact with Mr Trump’s lawyer, Jay Sekulow.

“I wanted Jay Sekulow, the president’s attorney, to know what was happening with the Mueller investigation. I did this because I support Donald Trump ... I wanted him to survive the Mueller investigation unscathed, which I believe he will, and I want him to be re-elected in 2020,” Mr Corsi said.