Lawyers for the estate of Michael Jackson sued Mann in January 2011, claiming he was violating copyrights and posed unfair competition to Jackson's estate. Mann has been collaborating with Katherine Jackson, Michael's mother, on several projects about Michael using his songs and images. Katherine Jackson is a beneficiary of Michael's estate.
Friday, U.S. District Judge Dean Pregerson sided with the singer's estate. Pregerson said Mann should be blocked from future uses of Michael Jackson's work.
The judge ruled that Mann's website improperly used art from the film "This Is It," a logo featuring Jackson and the song "Destiny," as well as other material. Mann had claimed he obtained rights to the works in a bankruptcy sale years ago, but the judge ruled Friday there was no evidence that the items could be used commercially.
Mann has worked with Katherine Jackson on several projects, including a book of recollections about her son. Several of the Jackson Secret Vault releases occurred at the same time as estate projects were being released, including the anniversary of Jackson's death and the release of the album "Michael" in December 2010.
An upcoming trial will address damages, although the judge noted that Mann and the site probably will not be able to pay any amount because of debts.
Mann's attorneys recently wrote in court filings that they hoped to introduce evidence during the upcoming trial that the singer's will was a fraud.
"The Executors of the Michael Jackson Estate are extremely pleased with the Court's ruling which prevents Mann from continuing to unlawfully profit from Michael Jackson and his intellectual property," said attorneys for Michael Jackson's estate in a statement issued Friday following the ruling.
Lee Durst, one of Mann's lawyers, Lee Durst, did not immediately comment on the case Friday.
The Associated Press contributed to this report.