It's a familiar sight at murder trials: grieving relatives clutching a victim's photograph as they sit in court.

And in one California case, those pictures could lead to the release of a convicted murderer.

In 1995, the mourning family members of Tom Studer (search) wore his photo on buttons during the trial of Mathew Musladin (search), who admitted shooting Studer in front of a San Jose home but who claimed it was in self-defense. Musladin was convicted of first-degree murder and is serving a life sentence without parole.

But the 9th Circuit Court of Appeals (search) ruled those buttons may have unfairly prejudiced jurors sitting 20 feet away. Defense attorneys argue that while seemingly innocent, such displays can affect the jury as strongly as any evidence.

"To the extent that the picture could be seen and a juror could be affected by it, then it should be excluded," said Oakland defense attorney John Burris. "You don't want any information in a courtroom that could impact a jury and generate sympathy."

But Studer's family is horrified at the thought that they might be the reason the painful case is reopened.

"I don't see how a picture of a person who was murdered ... can say automatically, this person was innocent, and the defendant is automatically guilty," said the victim's brother, Jim Studer.

The full 9th Circuit may review the decision, or the case may have to be re-tried. For now, Musladin is still behind bars.

Click in the box near the top of the story to watch a report by FOX News' Claudia Cowan.