A Los Angeles federal judge ruled today that Howard Mann, who had worked alongside the singer's mother Katherine, had been illegally using the material on his website Michael Jackson Secret Vault.
U.S. District Judge Dean Pregerson dismissed the businessman's claims he had obtained the rights in an old bankruptcy sale, and the website has since become inactive.
Representatives of the Michael Jackson estate sued Mann in January last year, claiming he was violating copyrights and posed unfair competition to it.
Judge Pregerson ruled that the website improperly used art from the film This Is It, a logo featuring Jackson and the song Destiny, as well as other material.
In his written judgement he said: 'In light of defendants' past and present infringement, it is also undisputed that future violations are likely, causing ongoing harm to plaintiffs and misled consumers.'
A trial will now take place to decide damages, although the adjudicator noted Mann and the website will probably be unable to pay any amount because of debts.
Disappeared: The dodgy website has since disappeared from the internet
Mann has collaborated with the singer's mother Katherine Jackson, who is a beneficiary of the 's estate, on several projects.
These include 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.
Family friend: Howard is seen here with Katherine Jackson in 2010
The businessman had claimed he obtained rights to the works in a bankruptcy sale years ago, but Pregerson ruled there was no evidence that the items could be used commercially.
Attorney Zia Modabber, who represented the estate in the case, said: 'The court's ruling makes clear that Howard Mann had no right to use Michael Jackson's intellectual property for his own benefit.'
Estate attorney Howard Weitzman said executors John Branca and John McClain are 'extremely pleased' by the ruling.
Violated: The judge ruled that Michael Jackson's copyrighted works were being used without his estate's permission