A former Mizuho Bank employee was arrested Saturday on suspicion of swindling ¥18 million from a 69-year-old Tokyo man through bogus investments in U.S. government bonds, police said.

Sadao Nomura, 52, allegedly defrauded the man, who is the chairman of a company that runs a public bath, in November 2003 by falsely claiming that Mizuho Bank was managing high-yield investments linked to U.S. government bonds not offered to ordinary customers, according to the Metropolitan Police Department.

Mizuho Bank does not deal with U.S. government bonds.

The police suspect Nomura swindled about ¥780 million from the man between 2003 and 2008 and about ¥460 million from 18 others, including his former coworkers.

Nomura, however, returned ¥540 million to the victims as interest, the police said.

Nomura admitted to the allegation, saying he used the money to bet on horses and play the stock market, the police said.

The fraud surfaced after Nomura rejected the Tokyo man's request to cancel some of his investments last year, prompting the man to consult the bank, the police said.

The bank fired Nomura last September.