London-listed coal miner Bumi said an independent probe had not been able to prove misuse of funds at its Indonesian units, as documentary evidence had been obtained illegally and key witnesses had refused to cooperate.
Bumi, one of the world's largest thermal coal exporters, was set up in 2010 by financier Nat Rothschild and Indonesia's politically connected Bakrie family, but the two sides are at loggerheads over the future of the company, which has become emblematic of concerns about the governance of foreign resources firms listed in London.
The Bakries aim to pull out of the venture and take back operational assets they brought in, while Rothschild is trying to keep the venture alive and change the board.
In recent months, the battleground for the founding investors has been the investigation into allegations of misuse and misappropriation of funds at Bumi's Indonesian operating assets, primarily Bumi Resources.
"Circumstantial evidence supports a number of the allegations but, due to the unwillingness of key parties to be interviewed and provide information as well as provenance issues, the allegations have not been substantiated," Bumi said on Tuesday.
The board did not publish the findings of the probe and said it was now in talks with Indonesian authorities - despite constraints linked to the origin of the whistleblower documents that triggered the probe - and Britain's Serious Fraud Office.
Bumi said investigators from London law firm Macfarlanes had met with resistance from unnamed individuals at part-owned Bumi Resources. The board also accused Rothschild himself of failing to cooperate by refusing to disclose details of the source of documents that led to the probe.
Bumi's long-awaited statement will disappoint investors hoping for closure on the group's legal issues. Citing Indonesian laws, the group's board gave away no details of the four-month investigation.
Under Indonesian law, Bumi said, it is a criminal offence to disseminate information that has been obtained illegally.
Bumi said a technical examination had shown the information was obtained "illegally by email hacking". "The board believes that there is no credible explanation other than that a large part or all of the materials which formed the basis of the investigation were obtained by such means," it said.
Rothschild, for his part, said there was no reason not to publish the report in either Britain or Indonesia.
"It is extraordinary that a report on the misappropriation of up to a billion dollars is more focused on settling scores with Nat Rothschild, than on following the money," Rothschild said in an emailed comment.
"The process is deeply flawed, but shareholders need not give up hope of recovering their money, although it is clear that the current board has neither the will, the wit, nor the energy for the task."
Bumi's board agreed earlier this month to call a shareholder meeting at which investors could, if they approve a resolution tabled by Rothschild, eject the current board. Rothschild is proposing a smaller board, which includes himself, a detail that has prompted outrage from his former partners.
Bumi said its audit committee had decided any further writedowns in the light of the Macfarlanes report were not likely to be material, given extensive writedowns already made on development assets at the heart of the probe.
It is also investigating why the issues currently being probed, many of which pre-date the creation of Bumi in 2010, were not uncovered by due diligence carried out at the time.