A federal judge has denied an appeal by the attorney representing the heirs of Superman's creators, clearing the way for Warner Bros. to gain access to documents the studio contends will demonstrate he “orchestrated a web of collusive agreements" that led the families to reject longtime deals with DC Comics.

The documents, which were stolen from the law offices of Marc Toberoff and delivered anonymously to Warner Bros. in December 2008. Although a judge at the time ruled that the documents were privileged and ordered them returned, it was determined that the attached seven-page cover letter was not protected by attorney-client confidentiality. That letter, dubbed the “Superman-Marc Toberoff Timeline," became the basis for the studio's 2010 lawsuit against the attorney, in which it claims he acted improperly to convince the heirs of Jerry Siegel and Joe Shuster to seek to reclaim the original copyright to the Man of Steel. Warner Bros. also alleges tht Toberoff schemed to secure for himself “a majority and controlling financial stake” in the Superman rights.

U.S. Magistrate Judge Ralph Zarefsky ruled late last month that those documents aren't protected by attorney-client privilege because Toberoff didn't fight a grand jury subpoena issued in the investigation of their theft, thus waiving privilege. However, the judge deferred the decision to presiding U.S. District Judge Otis Wright who, according to Hollywood, Esq., on Monday rejected Toberoff's argument that he had no choice but to cooperate with prosecutors in the burglary investigation.

Barring another appeal, Warner Bros. will finally get unfettered access to the documents that it hopes, at the very least, will force Toberoff, long a thorn in the studio's side, to resign as the Siegel family's attorney. Whether the papers are the legal hand grenade that Warner Bros. attorneys have made them out to be, demonstrating improper and even illegal, behavior, of course remains to be seen. Wright could look at the evidence and decide Toberoff's actions were merely those of an attorney aggressively soliciting clients and (just as aggressively) representing their interests.

If that's the case, it would make this lawsuit only the latest detour in the decade-long fight for Superman -- one that became even more bitter in 2008 following a ruling that Siegel’s widow Joanne Siegel and daughter Laura Siegel Larson had successfully recaptured half of the original copyright to the Man of Steel. The window will open in 2013 for Shuster’s estate to do the same.

Deadline's Nikki Finke offers spirited commentary on the Warner Bros. lawsuit against Toberoff, focusing on the stolen documents and the studio's controversial tactics.