The federal judge in the trial of ex-Trump campaign chairman Paul Manafort told Special Counsel Robert Mueller’s team on Thursday they cannot prove a key part of their case unless prosecutors call Manafort’s former business partner to the stand.

U.S. District Court Judge T.S. Ellis III issued the warning after prosecutors suggested Wednesday that Rick Gates – who is cooperating with prosecutors and had been considered a potential star witness – might not be called to the stand after all.

Referencing Gates, Ellis told prosecutors in court they “can’t prove conspiracy without him.”

“Not necessarily,” Mueller prosecutor Greg Andres responded, before saying they still have “every intention” to call Gates to the stand.

Ellis, a 78-year-old Reagan-appointed judge known for colorful comments, also quipped that his “wife wasn’t fooled” by the prosecution’s comments on Wednesday leaving open the option of not calling Gates — suggesting he did not believe the prosecution was being serious about the possibility.

But the Mueller team was rebuffed by Ellis on Wednesday when it first tried to introduce photos of Manafort’s closets, filled with suits and other high-end articles of clothing. Ellis noted that those photos would eventually become fodder for the media, and called them “unnecessary” for jurors to see.

“Enough is enough. We don’t convict people because they have a lot of money and throw it around,” he said. READ MORE: