Secret documents have revealed a deal hatched in an offshore tax haven to cash in on the myth, the aura and music of rock star Michael Hutchence.

The documents also reveal for the first time a claim of total ownership over a key part of Hutchence’s estate made by the performer’s former lawyer, Colin Diamond.

An investigation by Four Corners raises serious questions about how Diamond came to own some of Hutchence’s most personal belongings that were used in a recent Channel 7 documentary.

Those belongings include a diary and song lyrics left by Hutchence when he took his own life in a Double Bay hotel room 20 years ago.

“Everything of Michael’s in the room of the hotel was taken two days later by Colin Diamond,” Michael’s brother, Rhett Hutchence, told Four Corners.

“None of that stuff has ever been released to the family.”

How much money, if any, from newly-released music publicised in the Channel 7 documentary goes to Hutchence’s 21-year-old daughter, Tiger Lily Hutchence, remains deeply unclear.

Inside the secret documents

Details into Hutchence’s estate revealed in the Paradise Papers leak. Photo: ABC

The documents showing Diamond’s claim to be the “ultimate beneficial owner” of Hutchence’s estate have been revealed in the Paradise Papers leak from the law firm Appleby and other offshore service providers.

The investigation involves Four Corners working in partnership with the International Consortium of Investigative Journalists and other media partners, reviewing more than 13 million documents obtained by German newspaper Suddeutsche Zeitung.

The three-page handwritten document shows that a company called Helipad Plain was formed in the tax haven of Mauritius in late 2015, in a deal between Diamond and music entrepreneur Ron Creevey.

The man claiming the estate

Lawyer Colin Diamond first became involved with Hutchence in Hong Kong when the rock star started placing his assets in complicated offshore trusts to avoid tax in the 80s and 90s.

Hutchence’s music rights were held through a British Virgin Islands company called Chardonnay Investments.

Michael Hutchence’s former lawyer Colin Diamond. Photo: AAP/Seven Network

Diamond took centre stage in Seven’s recent documentary, in which he discussed the diary left in the hotel room after Hutchence’s death.

“I have held on to it for Tiger for many years,” Diamond said.

The Seven documentary explained Diamond had the diary and sensitive personal documents from Hutchence’s hotel room because he was Hutchence’s friend and co-executor of his will.

Rhett Hutchence told Four Corners: “Two days after Michael died, Colin Diamond went into the Rose Bay Police Station, acting as Michael’s attorney, and took hold of all of Michael’s possessions that he had with him in Australia.

“He kindly left the belt that Michael used for my father to pick up.

“My father was — I mean, the whole family was completely shocked that he had actually taken all this stuff.

“That should have been part of the estate. It’s the family stuff.”

The documentary did not explain exactly how Diamond came to be the man who controls Hutchence’s estate.

Michael Hutchence had made Diamond executor of his will, partly because of the difficult relationships in his close family.

Hutchence’s missing millions

Hutchence’s family have had no answers on his will. Photo: AAP

Diamond’s claims on Hutchence — before and after his death — were controversial when Diamond first acted as a lawyer to Hutchence.

“I think pretty early on he was problematic. Chris Murphy, the band’s manager at the time, advised them that he was not to be trusted, and this was not the way to go,” said veteran rock journalist and a biographer of Hutchence, Toby Creswell.

“He was just, like, the toughest guy in the jungle really. And he was going to outlast anybody else who was going to get in the way of the fortune.”

Michael’s late mother, Patricia Glassop pursued the estate’s assets held in labyrinthine offshore structures through the Queensland Supreme Court, naming Diamond and others as defendants.