Paul Manafort is going to jail. A federal judge in Washington, D.C., ruled Friday morning to revoke his bail, meaning the president’s former campaign chairman will be incarcerated until his September trial.

The move came after special counsel Bob Mueller’s team moved for the judge to change the terms of Manafort’s bail. Mueller’s team alleged that Manafort and Konstantin Kilimnick—a former colleague of Manafort’s who the special counsel recently indicted—tampered with witnesses in the months after being charged with a host of crimes.

Last week, a grand jury handed down a superseding indictment of Manafort charging him with obstruction of justice, on top of prior charges of conspiracy against the United States, tax law violations, and illegal lobbying.

The issue was communications Manafort and Kilimnick had with Eckhart Sager and Alan Friedman, two public-relations professionals. Manafort had enlisted the pair in 2012 to help boost his lobbying efforts on behalf of pro-Putin Ukrainian President Viktor Yanukovych. Manafort and his team had put together a team of former European politicians to lobby in Europe and the United States for Yanukovych, and the P.R. pair helped organize their work. Mueller alleges that that lobbying work violated American disclosure laws; Manafort, according to Mueller, asked Sager and Friedman to lie to investigators by saying the lobbying was only in Europe, not in the United States.

This past week, court filings revealed a new piece of Mueller’s evidence boosting his argument: a memo detailing plans the two P.R. pros made with Manafort regarding the lobbying effort.

Paul Manafort’s former partner, Rick Gates, has begun cooperating with Mueller, putting even more pressure on Manafort.

Trump has tried to distance himself from Manafort. In a press gaggle on Friday morning, the president said Manafort only worked for him for 49 days. That is incorrect: Manafort worked on Trump’s campaign for nearly five months.

The president also said he feels “a little badly ” for Manafort.

“They went back twelve years to get things that he did twelve years ago?” he said.