Light was cast on a long-running Scottish Socialist Party mystery during the evidence of its former MSP, Rosie Kane.
The perjury trial jury has heard several references to an affidavit, sworn by an unnamed senior figure in the party and given to a Sunday newspaper.
The statement was said to have given "explosive details" about an emergency executive committee meeting on 9 November, 2004, when Tommy Sheridan is alleged to have confessed to attending a sex club.
It was following that meeting that Sheridan stood down as party leader, citing a desire to devote more time to his pregnant wife and child.
The trial has been told that an investigation was demanded to try to discover the source of the affidavit, but Ms Kane said it was only recently that she learned the identity.
"The person concerned has since told me… it was Alan McCombes. I knew nothing of it at the time, and I only learned about it just before this trial began," Ms Kane told the court.
"For whatever reason, he felt it necessary that he went to the press."
The jury has heard that Mr McCombes, partner of the former MSP Carolyn Leckie, was the party member who went to jail on the eve of Sheridan's defamation action for refusing to hand over minutes of the "confession" meeting.
After Sheridan's resignation, Mr McCombes stood in the election for the post of national convener, but lost to Colin Fox.
Several witnesses are being recalled to be questioned by Sheridan, now that he is conducting his own defence.