Paul Manafort is heading to jail.

On Friday morning, a Washington, DC, judge ruled that the former Trump campaign chair had violated his conditions for release on house arrest and will be sent to jail as he awaits trial.

“I have struggled with this decision,” Judge Amy Berman Jackson said. But she concluded that she couldn’t come up with a release order she could issue that would prevent Manafort from further attempts at witness tampering, which he was indicted for last week. “This is not middle school, I can’t take his cell phone,” she said.

After expressing concern that Manafort seemed “inclined to treat these proceedings as just another marketing exercise,” Jackson said he had “abused the trust” placed in him by the court system and ordered him detained pending trial.

Manafort gave a brief wave before being led out of the courtroom.

It’s the latest blow for Manafort, who’s been the primary focus of charges in special counsel Robert Mueller’s investigation of Russian interference in the 2016 election. Mueller first indicted Manafort in DC last October, added more charges in Virginia this February, and added yet more charges in DC just last week.

Mueller’s most recent accusation is that Manafort and a longtime business associate, Konstantin Kilimnik, tried to tamper with witnesses in his upcoming trial by contacting them and encouraging them to give a false story.

The special counsel’s team said they’d obtained encrypted messaging, call records, and witness testimony to back up this charge, and got a grand jury to indict Manafort and Kilimnik on counts of obstruction of justice and conspiracy to obstruct justice last week. They also said Manafort violated his conditions of release.

Judge Jackson didn’t need to rule on whether Manafort was actually guilty of the new charges. For today’s hearing, she just had to determine whether Mueller had demonstrated probable cause that he had committed crimes. And she concluded that he did — and that he should be detained to await trial as a result.

Manafort is currently facing a combined total of 25 charges spread over two venues. His Virginia trial is currently scheduled to begin on July 25, and his DC trial on September 17.

The charges against Manafort so far don’t explicitly relate to the primary purpose of Mueller’s probe: Russian interference in the 2016 campaign. Instead, they focus on Manafort’s lobbying and foreign work for pro-Russia Ukrainian interests prior to the campaign, his finances, and, now, alleged witness tampering. (Manafort has pleaded not guilty on all counts.)

However, it’s widely thought that Mueller’s team is trying to pressure Manafort to “filp,” with the belief that he has important information to the larger Russia probe. A stay in jail will add to that pressure — Manafort has spent years living a high-flying lifestyle and likely won’t find jail a pleasant experience.

Why Judge Jackson ordered Manafort sent to jail

Mueller’s team claimed in their February indictment that as part of the Manafort’s lobbying for the Ukrainian regime, he paid a group of former senior European politicians that he called the “Hapsburg group” to advocate for Ukraine’s interests in the United States.

After the indictment, Manafort seemed to believe his strongest defense would be to claim that he did pay these politicians to advocate for Ukraine’s interests — but only in the European Union, not the United States. And he wanted to make sure that two unnamed people from a PR firm with whom he’d worked on the project would stick to that story.

So, per Mueller, within days Manafort tried to reach out to one principal in that PR firm — someone referred to as “Person D1” in the indictment. Mueller alleges that:

On February 24, Manafort called Person D1, but he quickly ended the call.

That same day, Manafort used an encrypted messaging app to text the person, “This is paul.”

On February 25 and 27, Manafort tried to call Person D1.

On February 26, Manafort sent Person D1 an encrypted message with a news article about the Hapsburg group allegations, and then wrote: “We should talk. I have made clear that they worked in Europe.”

But Person D1 talked to the FBI instead. He said that, contra Manafort’s claims, he knew the Hapsburg group worked in the United States too. And, Mueller alleges, Person D1 thought Manafort was trying to suborn perjury.

Another set of surreptitious communications came from a longtime associate of Manafort’s whom the special counsel had previously called “Person A.” We now know that person is Konstantin Kilimnik, a longtime business associate of Manafort’s who’s been called his protégé. (Mueller has claimed in court filings that Kilimnik has ties to the GRU, Russia’s foreign military intelligence agency.)

Mueller claims that in February and April of this year, Kilimnik repeatedly tried to contact the two PR firm principals on behalf of someone he called “my friend P.” This person also tried to emphasize Manafort’s message that the Hapsburg group “never lobbied in the US.”

The second PR firm principal, “Person D2,” also told the FBI that he knew this wasn’t true, and that the Hapsburg group did in fact lobby in the US. (Persons D1 and D2 were identified as public relations executives Alan Friedman and Ekhart Sager in an accidentally unredacted court document.)

Because of these contacts and this testimony, Mueller got his DC grand jury to charge Manafort and Kilimnik with charges of obstruction of justice and conspiracy to obstruct justice. And now, Judge Jackson has agreed there’s probable cause that Manafort violated his releases conditions by committing other crimes — and sent him off to jail.