Judge Juan Merchan asked the jurors to leave the courtroom so he could admonish Costello over his behavior on the stand.

Evidence

Who is Robert Costello, the Trump witness accused of staring down … (The Hill)

corroborated: 2 independent passages support this claim
XREF: connects to: Ellis’s apparent stumble was mischaracterized by the prosecution. — Lynley Hood, A City Possessed, 2868; After sending reporters out of the courtroom, judge threatened to hold Robert Costello in contempt if the witness continued to stare at him. — Judge erupts in Trump hush money trial over witness …; Judge Merchan briefly booted the public after scolding defense witness Robert Costello. — Prosecutors rest their case against Donald Trump in dramatic day of … (+4 more)

Judge Merchan accused Costello of exhibiting ‘contemptuous’ conduct and threatened to remove him from the stand if he tried to stare him down again. (similarity 0.93)
Judge Merchan briefly booted the public after scolding defense witness Robert Costello. (similarity 0.92)
The judge briefly cleared the courtroom while he admonished the witness and threatened to kick him off the stand. (similarity 0.90)
Judge Merchan said ‘Sir, your conduct is contemptuous right now’ and cleared the courtroom to admonish Costello. (similarity 0.90)
After sending reporters out of the courtroom, judge threatened to hold Robert Costello in contempt if the witness continued to stare at him. (similarity 0.89)
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. (similarity 0.87)
Robert Costello was called as a defense witness and quickly admonished by the judge for being contemptuous. (similarity 0.87)
The judge in Donald Trump’s Manhattan criminal trial cleared the courtroom on Monday to reprimand a witness and ally of the former president. (similarity 0.81)