(Bloomberg) -- Japanese prosecutors alleged that the Tokyo Olympics sponsorship process was tainted by bribery, arresting on Wednesday a former senior member of the organizing committee and three men linked to the clothing company that dressed the Japanese Olympic team.

Prosecutors suspect former Tokyo 2020 organizing committee executive board member Haruyuki Takahashi of taking a total of 51 million yen ($378,000) between 2017 and 2021 from executives seeking favorable treatment for sponsorship and licensing contracts.

Aoki Holdings Inc. founder and former Chairman Hironori Aoki, former Executive Vice Chairman Takahisa Aoki and current Senior Managing Executive Officer Katsuhisa Ueda were arrested on suspicion of making bribes, the company said. More than 50 payments were made to the account of a company run by Takahashi, prosecutors said in a statement.

Takahashi denies the allegations and has told prosecutors the payments were a fair amount for sports consulting services, Japanese broadcaster TBS reported late on Wednesday local time, citing an unidentified person.

Aoki Holdings operates an office wear chain across Japan. It signed on as a Tokyo 2020 sponsor in 2018 and designed Japan’s Olympic and Paralympic uniforms. The company said in a press release that it’s been cooperating fully with the investigation and will continue to do so.

Takahashi is a former senior managing director of advertising giant Dentsu Inc. He had left the company before the Tokyo Olympic organizing committee appointed Dentsu in 2014 to assist it with marketing and sponsorship. Dentsu Inc. is now a unit of Dentsu Group Inc. after a change in holding company structure. 

Dentsu Inc. said by email that it’s fully cooperating with the investigation. A spokesperson for the Japanese Olympic Committee wasn’t available by phone.

Shares of Dentsu Group declined 0.9% as of 1 p.m. in Tokyo, in line with the broader Topix index and paring declines from the morning session. Aoki Holdings shares rose as much as 5.2% on Thursday after closing lower Wednesday following reports of the arrests.

The Games had yielded a hefty $3.3 billion from sponsors by the time they kicked off in 2021, after being postponed from a year earlier due to the Covid-19 pandemic.

(Updates with report of Takahashi’s denial of the allegations, and adds share moves. An earlier version of this story was corrected to clarify that Takahashi’s role at Dentsu Inc. preceded the formation of Dentsu Group Inc.)

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