The Salt Lake City-based church has filed a notice of claim against a corporation set up by Blackmore, who is one of two leaders in a commune in southeastern B.C. known as Bountiful. Blackmore and his followers practise a fundamentalist form of Mormonism that still holds polygamy as a tenet of the faith.
The Canadian arm of the Mormon church says it tried to register Church of Jesus Christ of Latter-day Saints in Canada with B.C.'s corporate registry, but the application was rejected.
The registry indicated the church's proposed name was too similar to the Church of Jesus Christ of Latter Day Saints Inc., which was registered by Blackmore in 2010, according to the statement of claim.
The lawsuit alleges Blackmore is attempting to suggest his group is sanctioned by the official church, which renounced polygamy more than a century ago and has disavowed any connection to Bountiful or similar polygamous groups in the United States.
"Adopting for its corporate identity the name 'the Church of Jesus Christ of Latter Day Saints Inc.' ... is yet another attempt of the Blackmore sect to convey a false impression of affiliation with the church," says the notice of claim, filed earlier this week in B.C. Supreme Court.
"The plaintiffs do not endorse, condone or support the Blackmore sect's practices and tenets."
The Mormon church seeks a declaration that Blackmore's corporate name violates its trademarks and an injunction ordering his sect to stop.
Blackmore leads one of two divided factions in Bountiful, which is in the southeastern corner of the province a short distance from the U.S. border.
One side of the community is connected to the Fundamentalist Church of Jesus Christ of Latter-day Saints, or FOLDS, and its jailed leader Warren Jeffs. Blackmore and his followers split off from that group more than a decade ago.
Bountiful has been the subject of numerous police investigations since the early 1990s amid allegations of polygamy, sexual abuse and human trafficking.
In 2009, Blackmore and James Oler, who led the other faction at the time, were each charged with one count of practising polygamy. Those charges were later thrown out after a judge ruled the prosecutor handling the case was chosen improperly.
The collapse of that prosecution prompted the government to launch a constitutional reference case, which ended in 2011 with a judge upholding the anti-polygamy law as constitutional.
The RCMP currently have yet another investigation into Bountiful. A special prosecutor has been appointed to review evidence and consider charges that could include human trafficking, child exploitation and polygamy.
The investigation followed evidence, presented at the constitutional reference hearing, that alleged dozens of teen brides were spirited across the U.S. border to marry older men.
A special prosecutor was appointed in 2012 to handle the case, but there has yet to be any word on potential charges.
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