A former senior executive of a Japanese pension fund admitted Saturday to embezzlement in a scandal in which billions of yen in company pension money was lost.

Yoshinobu Sakamoto, 55, the former general manager of the Nagano Prefecture construction employees' pension fund, was arrested in Bangkok on Friday for being in the country illegally.

Thai immigration officials said Sakamoto, who is wanted by Japanese police, would be sent back to Japan pending completion of extradition procedures.

Sakamoto, whose passport expired in September 2011, paid a 1,800 baht (¥5,700) fine on Saturday after a court appearance.

Speaking to reporters, Sakamoto said he had already spent all the embezzled funds but declined to elaborate on how he used the money.

"(I'll talk) after returning to Japan," he said.

The Nagano construction employees' pension fund is one of the 17 Japanese funds defrauded by AIJ Investment Advisors Co., which has been renamed MARU.

The Nagano pension fund had entrusted ¥6.5 billion to AIJ, which lost more than half of the ¥14.5 billion in pension money that was under its management.

The Nagano fund also said ¥2.3 billion of its money had been misappropriated between 2005 and 2010.

Sakamoto fled to Thailand in September 2010 after the Nagano fund filed complaints over the misappropriation with police.

The owners of an apartment in western Bangkok where Sakamoto hid until shortly before his arrest said he seldom left his house and lived modestly.