(GREENSBORO) -- The judge overseeing John Edwards' criminal trial closed the courtroom Friday to talk with attorneys about a juror issue. The jury's behavior drew attention Thursday when four alternate jurors wore yellow shirts.

On Friday, they all wore red, as did two of the 12 jurors deliberating the case. Former federal prosecutor Kieran Shanahan said, "If there was any deliberations which took place outside the presence of the jury, that could be basis for a motion for mistrial."

Shanahan said he has never seen such unusual behavior as the color-coordinated clothing. Before sending the jury home after six days of talks, Judge Catherine Eagles warned them not to discuss the case outside of the deliberation room.