'Are you staring me down?': Fiery moment between judge, defense witness in Trump hush money trial

In a fiery moment in court on Monday, Judge Juan Merchan reprimanded a key defense witness testifying in former President Donald Trump's hush money trial.

Robert Costello -- an attorney and longtime Trump ally -- took the stand Monday afternoon to testify about a meeting he had with Michael Cohen in April 2018 after the FBI raided Cohen's home and office.

As Merchan sustained a string of objections by the prosecution on procedural matters, Costello could be heard sighing loudly and uttering the words "ridiculous" or "jeez" from the witness stand. Less than 15 minutes into Costello's testimony, the typically even-tempered judge appeared fed up with Costello’s behavior and sent the jury out of the courtroom.

"I'd like to discuss proper decorum in my courtroom," he said. "If you don't like my ruling, you don't say 'Jeez,' you don't say 'Strike it,' because I'm the only one who can strike testimony in the court. If you don't like my ruling, you don't give me side-eye, and you don't roll your eyes."

Costello replied, saying he understood.

But then, in an abrupt comment, Merchan addressed Costello again.

"Are you staring me down?" he asked, visibly angry.

A furious Merchan then ordered all 60 reporters to clear out of the courtroom, sending the confused crowd into the hallway.

A few minutes later, both jurors and reporters were allowed back inside, and Merchan continued proceedings without addressing things with Costello any further.

According to a court transcript obtained by ABC News obtained after Monday’s proceedings, Merchan accused Costello of exhibiting "contemptuous" conduct on the stand.

"Your conduct is contemptuous right now. I'm putting you on notice that your conduct is contemptuous. If you try to stare me down one more time, I will remove you from the stand. I will strike his entire testimony; do you understand me?" Merchan asked Costello.

Defense attorney Emil Bove said he understood. Costello asked if he could "say something," to which the judge refused, saying, "This is not a conversation," to which Costello replied “OK.”

Costello's time on the witness stand continued without incident as he testified about his April 2018 meeting with Cohen. Costello said Cohen was acting "manic" at the meeting after the FBI raid and kept "pacing back and forth."

Costello testified that Cohen told him he didn't "have anything on Donald Trump," and he said he asked what his "escape route" would be.

"[Cohen said], 'My life is shattered, my family's life is shattered,'" Costello testified.

According to Costello, Cohen was "suicidal" that day.

“He was putting on quite a show, and he explained to us that two nights before, he was on the roof of the Regency Hotel, and he was going to jump off and kill himself because he couldn’t handle the pressure" of the situation, Costello testified.

Last week, Cohen testified that he "didn't trust" Costello, who he said was "incredibly close to Rudy Giuliani," adding that he feared anything he told him would get back to Trump. On the stand, Cohen said their relationship took a turn in June 2018, when he said he began considering other attorneys to represent him.

In March 2023, Costello testified before the grand jury as an exculpatory witness at the request of Trump's attorneys. He also told reporters last year that Cohen is “on the revenge tour” and cannot provide reliable testimony.

Cohen, in his testimony, accused Costello of spearheading a "pressure campaign" to keep him from flipping on Trump. (Trump has denied any wrongdoing and pleaded not guilty to the charges in the case.)