Shortly after FBI agents raided the home and office of Donald Trump’s attorney, Michael Cohen, it was announced that the investigation into Cohen would be conducted and overseen by the U.S Attorney’s office for the Southern District of New York. Apparently, Special Counsel Robert Mueller had handed off that part of the unfolding case against Donald Trump to another prosecutor.

However, now we know that Mueller did keep part of the Cohen probe for himself. Specifically, the part that relates to Russia and Ukraine.

On Monday, we learned that Andrii Artemenko, a Ukrainian politician, will appear before Mueller’s grand jury on Friday, reportedly to talk about a Russia-Ukraine peace plan that was being floated in 2016 and would have resulted in American sanctions being lifted on Russia. As Politico reports:

“The Artemenko case is one of the more unusual developments in the investigation into possible Russian interference in the 2016 election. The New York Times reported in February 2017 that Artemenko had contacted Felix Sater, a former business associate of Trump’s, to find out how he could make his plan for peace in Ukraine known to the Trump administration. Sater introduced Artemenko to Micheal Cohen, who left the plan in the office of then-national security adviser Michael Flynn, the Times reported. (Cohen has denied that, saying he threw the document away.)”

Now consider the following:

• Michael Flynn is already cooperating with the Mueller team.
• Mueller clearly sees the “peace plan” as proof of a larger criminal conspiracy between members of the Trump campaign and the Kremlin.

Obviously, Mueller is about to put pressure on Cohen via the grand jury, which is bad news because that means Cohen’s attorney will have to try and defend him on multiple fronts. Facing decades in prison, will Cohen be willing to keep silent and do his time like a good Trump loyalist?

Some have said that Cohen will never turn on the president; he’s that loyal to Trump. But even if Cohen doesn’t flip, the grand jury could still return indictments against both Cohen and his most famous client. Either way, it now appears that Cohen will be the link to Trump that winds up bringing down the administration with a giant crash.