Factbox: Key executive players in the Olympus scandal

TOKYO (Reuters) - Japanese prosecutors raided Olympus Corp and the homes of former executives on Wednesday over a $1.7 billion accounting scandal that has threatened the survival of the once-proud camera and medical equipment maker.

Following are profiles of former senior executives that an external panel accused of either helping to craft the scheme to cover up losses on speculative investments or knowing about it.

HISASHI MORI

Mori joined Olympus in 1981 and rose relatively quickly to become executive vice president in April this year.

A former head of Olympus's corporate social responsibility unit, Mori initially defended a series of merger and acquisition payments being questioned by ousted chief executive Michael Woodford. But he later confessed to current President Shuichi Takayama that the company had been systematically covering up losses for years.

The panel report said Mori, 54, had played a major role in the cover-up, alongside Hideo Yamada. Mori was fired for his involvement in the scheme, and also resigned as a director last month.

HIDEO YAMADA

The panel found that Yamada, along with Mori and investment bankers, had crafted a scheme as long ago as 1998 to conceal losses.

Yamada, 66, was appointed standing internal auditor in June this year, meaning he held the post during the period Woodford spent questioning past acquisitions. He had joined the company in 1963 at the age of 18 and has spent little time in the public eye. He resigned from his position last month.

TSUYOSHI KIKUKAWA

A gravelly voiced chain smoker, who went by the nickname "Tom" among English speakers, Kikukawa, 70, has been accused by Woodford of running the company like an emperor in his decade as president.

After graduating from prestigious Keio University, he joined Olympus in 1964 and worked his way up the corporate ladder in public relations, corporate planning, finance and accounting before taking the presidency in 2001.

Known for his affable personality and fondness for his pet poodles, Kikukawa stepped down on October 26 and has not appeared in public since he announced his former protege Michael Woodford had been fired as chief executive.

He quit as a member of the board last month, hours before he would have faced a boardroom showdown with Woodford. The third-party panel report said he was aware of the scheme.

MASATOSHI KISHIMOTO

Among the former presidents the external report says were aware of the scheme, Kishimoto joined Olympus in 1958, worked mainly on expanding the company's business overseas and took over as president in 1993, stepping down in 2001. He served as chairman until 2005.

He received a number of awards from various governments for his contributions to industry, including a Japanese award for helping the camera industry adapt to the digital age. Digital cameras are one of a few high-tech products dominated by Japan.

Kishimoto's predecessor as president, Toshiro Shimoyama, told the Nikkei business daily that Kishimoto had been in charge of finances during Shimoyama's own 1984-1993 presidency.

(Reporting by Isabel Reynolds; Editing by Chris Gallagher)