Edmonton Mayor Stephen Mandel, seen speaking to reporters at city hall on Monday, has hired U.S. lawyers to force Twitter and two other companies to turn over information, his Canadian lawyer says. (CBC)Court documents reveal more details about Edmonton Mayor Stephen Mandel's defamation lawsuit against a campaign volunteer for his main challenger in the recent municipal election.

All documents in the lawsuit were sealed by an Alberta Court of Queen's Bench judge when Mandel filed the $500,000 action against Nathan Black two days after the Oct. 18 election.

The documents were unsealed Monday by Alberta Court of Queen's Bench Justice Donna Read after she heard arguments from a lawyer representing CBC and the Edmonton Journal.

Mandel's lawyer, James Thorlakson, argued that the documents cannot be made public until an investigation is complete. But the judge disagreed with him.

"The courts are open," Read told the court. "Freedom of expression exists. There is no good reason for that statement of claim to be sealed."

The lawsuit centres on a blog posting from Oct. 7 written by someone billed as "darrensbigscoop." The posting accused Mandel of having a conflict of interest when making decisions about the future of the City Centre Airport.

The statement of claim alleges Black was the "source of the statements" in the blog "and that he made those statements to persons whose identities are unknown to the plaintiff at this time." These allegations have not been proven in court.

Black told CBC News on Monday he hadn't been served with the statement of claim nor had he seen any legal documents.

The court documents reveal Mandel wants three U.S. companies — Automattic, owner of blog publishing software WordPress; Twitter; and USB phone device provider MagicJack — to reveal the name, address, contact information and IP addresses of the individuals associated with "darrensbigscoop."

Black denies writing blog posting

Council voted in July 2009 to close the airport just north of downtown Edmonton so the land could be freed for development. But an unsuccessful petition drive by Envision Edmonton to force a plebiscite on the closure made the airport's future an election issue.

Black — a volunteer for Envision Edmonton and pro-airport mayoral candidate David Dorward — has admitted he posed as a fictional Seattle journalist to make phone calls to city councillor Amerjeet Sohi and Sid Hanson, an organizer for pro-closure group Yes for Edmonton.

Black spoke to Sohi and Hanson about the airport issue but denied writing the blog posting. Dorward condemned Black's actions and said he was no longer welcome on his campaign after Black admitted to calling the two men.

The article from "darrensbigscoop" was published using blogging software WordPress. The posting was also promoted on a Twitter account belonging to "darrensbigscoop".

Sohi and Hanson were contacted by a phone number with a Seattle area code that was set up through MagicJack.

Thorlakson alleges all three accounts were arranged to make it appear as though all information was coming out of Seattle.

"This person has gone to great lengths to remain unknown," he told court.

According to Thorlakson, Mandel has retained lawyers in San Francisco to compel the three U.S. companies to reveal all the contact information for each account.

If Mandel wins his lawsuit, he plans to donate the money to the Edmonton Community Foundation to help children in need.