A former Wall Street banker of Japanese descent has emerged as a key figure in the scandal engulfing Japanese blue-chip firm Olympus Corp, according to documents provided by the firm's ex-CEO.

The veteran banker, Hajime 'Jim' Sagawa, owned an obscure U.S. financial firm which was hired by the endoscope-maker five years ago to provide what later turned out to be stunningly expensive advice, a fee of $687 million, the documents show.

Reuters went to Sagawa's Florida home on Thursday, but the ex-Nomura banker was not in. Instead, his wife Ellen said he was traveling and that he had done nothing wrong.

My husband was on Wall Street for many years and was well-respected, she said after answering the door of their waterside two-story home in Boca Raton, north of Miami.

My husband is clean as a whistle, I assure you, she said when asked about Sagawa's connection with the scandal which has wiped out half Olympus's market value, outraged major shareholders and been drawn to the notice of regulators.

She gave Reuters her husband's cell phone number but calls went to voicemail and he did not immediately return them.

Former Olympus CEO Michael Woodford, barely a fortnight into his tenure in the top job, raised the alarm on the huge advisory fee after his sudden sacking last week. The sum was equal to a third of the 2008 takeover deal to which it related -- compared with the 1-2 percent bankers usually charge.

Woodford, now in the UK, gave Reuters a copy of an independent inquiry into the fee, which was paid in relation to Olympus's $2.2 billion takeover of UK medical equipment firm Gyrus. He had commissioned the inquiry from accountancy firm PricewaterhouseCoopers (PwC) while he was still an executive.

PwC has declined to comment on the report, which is marked confidential and carries no date for when it was compiled.

Olympus, which denies any wrong-doing over the fee payment, has not given details on the identities of the advisers who earned the fee, other than acknowledging that the fees were paid to two obscure firms, AXES and AXAM Investments.

The PwC report identifies Sagawa as the principal of AXES, which was the main advisory firm, though it does not claim to know where the money trail finally ends.

Sagawa represented AXES in relation to the Gyrus transaction who we understand has resided in the United States from 1980 to the present, including a period stationed in New York for Nomura Securities, the PwC report said.

It said Sagawa, who also worked for Drexel Burnham and PaineWebber before setting up AXES, was AXES president and held himself out to be a director of affiliated firm AXAM which ultimately received the bulk of the fee.

We understand that members of the board may have had previous dealings with Sagawa prior to his involvement with AXES, the PwC report said.

But it added: In relation to Olympus' acquisition of Gyrus, we understand that the board confirmed that there were no personal vested interests between themselves and Sagawa or AXES.

Sagawa's wife denied he was a director of AXAM, incorporated in the Cayman Islands, a tax haven. But she said she had only limited knowledge of her husband's businesses.

Woodford has notified regulators in Japan and fraud investigators in his native Britain of his concerns, though he too has stopped short of making specific allegations of wrong-doing at Olympus. He says he was sacked for asking questions.

Before his dismissal, he sought the resignations of Olympus Chairman Tsuyoshi Kikukawa and senior executive Hisashi Mori.

The eventual cost of the transaction to Olympus is extremely significant and is as a result of a number of actions taken by management which are questionable and which give cause for concern, the PwC report said.

Based on the review we have undertaken to date, we were unable to confirm that there has been improper conduct, however, given the sums of money involved and some of the unusual decisions that have been made it cannot be ruled out at this stage, it concluded.

The report said AXES was a dormant company, and a security guard at its New York address said the firm's office had been closed for a couple of years. Contact numbers for AXAM could not be found and the PwC report says the firm was struck off the Cayman Islands registry in last year.

(Reporting by Kevin Gray in BOCA RATON, Tim Kelly in TOKYO, Kirstin Ridley and Alex Smith in LONDON. Writing by Mark Bendeich; Editing by Neil Fullick)

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