OSAKA -- The 62-year-old head of a group affiliated with a major crime syndicate and three other senior members of the gang were arrested Friday on suspicion of usury, police said.

Masahiko Kawasaki, an Osaka resident who heads the Isshin-kai, which is associated with the Yamaguchi-gumi gang, was charged, along with the three others, of violating consumer finance law.

Police said they believe profits from exorbitant interest rates on loans from the group's money-lending firm were used to fund the group's activities. Another senior member of the group is being sought on the same charge.

According to police, Kawasaki and the others opened and managed the money-lending firm in Osaka, where the group is based.

They charged an extremely high interest rate on a loan, which was repaid between January and March 2000, to the president of an Osaka electrical engineering firm.

Investigations showed that on the estimated 7 million yen lent to the company president, the interest rate was 0.17 percent to 0.23 percent a day, more than the 0.11 percent legal limit at the time. The current limit on interest rates for loans is 0.08 percent.

In total, police said, the four collected about 1.26 million yen in interest from the company president, more than twice the legal maximum.

The engineering company president, who went to the money-lending firm after he was unable to borrow money from a bank, declared bankruptcy in October 2000 due to dried up cash flows, police said.

The Yamaguchi-gumi is among the 25 organizations in Japan designated as crime syndicates by prefectural public safety commissions.