The face mask former Minneapolis police Officer Derek Chauvin has been required to wear during his trial in George Floyd’s death has hidden his reaction to testimony, including any sympathy or remorse that legal experts say can make a difference to jurors.

Because coronavirus concerns have forced Chauvin and other participants to wear masks except when they’re addressing the court, the enduring image of the defendant throughout the trial has been his impassive expression from last May as he gazed at the teenager filming his knee pinning Floyd’s neck. The girl, who captured the encounter on her cellphone, called Chauvin’s stare “cold” and “heartless.”

Prosecutors have repeatedly displayed the image in the courtroom, and Minneapolis Police Chief Medaria Arradondo alluded to the white former officer’s facial expression as he explained why he violated department policy by kneeling on the Black man’s neck for an extended period. Legal experts say the image — and the challenge of replacing it in jurors’ minds with Chauvin’s reactions — could hamper the defense.

“Every trial has a hero and a villain,” said Ryan Pacyga, a defense attorney who has been following the trial. “He looks like a villain.”

Trial lawyers, who have long practiced the art of courtroom dramaturgy, send subtle hints to jurors about a defendant through their looks and body language. They say that it humanizes the defendant.

“You’ve got to find a way for the jury to care for them,” Pacyga said.

But the pandemic has changed how the trial works.

Chauvin didn’t appear to show any emotion during the videos or testimony as he scribbled notes on a notepad. But it also would be difficult to see if he was affected because the bottom half of his face is hidden behind a face mask.

“I wonder if watching these videos causes him some pain and agony? I don’t know,” said Joseph Daly, emeritus professor at Mitchell Hamline School of Law in St. Paul, Minnesota.

Research by legal scholars has shown that defendants who appear to show remorse may have an advantage with juries.

“People who look more angry are more likely to be viewed as being a criminal,” said Kim MacLin, a professor at the University of Northern Iowa who specializes in psychology and law.

She conducted an experiment that found jurors in a mock trial were more likely to acquit if they saw an image of the defendant that seemed remorseful.

“It is something that juries, by human nature, think about. What sort of person are we dealing with here?” said Susan Bandes, an emeritus professor at DePaul University College of Law. She noted that Chauvin already has a “remorse deficit” due to his actions during Floyd’s arrest, adding, “That look on his face as captured in the video is so powerful.”

Attorneys often try to cast defendants in a positive way by making sure they are wearing a suit that fits, getting them to smile at breaks in proceedings or asking their family or friends to appear in the courtroom.

Chauvin’s defense attorney touched him on the shoulder while he was introduced during jury selection, when Chauvin was allowed to briefly take his mask off.

Daly said it is a way for the attorney to send a subtle message to jurors: “I’m not afraid of this guy.”