TOKYO >> Japanese prosecutors raided the headquarters of major advertising company Dentsu on Friday, as the investigation into corruption related to the Tokyo Olympics widened.

Major local TV broadcasters showed Tokyo District Prosecutors and Japan Fair Trade Commission officials entering Dentsu headquarters.

Dentsu dominates event organizing, marketing and public relations in Japan. It helped land the 2020 Games for Tokyo, and then lined up record domestic sponsorships.

Haruyuki Takahashi, a former executive at Dentsu, has been arrested four times in recent months on charges of receiving bribes from various companies that became sponsors for the Games.

The latest investigation centers around bid-rigging for companies to be picked to work on test events, according to Japanese media reports. The test events started in 2018, spanning various sports including sailing and weightlifting, to prepare for the Olympics. Being chosen for test events is critical to being picked for actual Olympic venues.

The money that exchanged hands for the bid-rigging totaled $3.6 million, involving nine companies and one organization, according to the newspaper Nihon Keizai Shimbun and other reports.

The companies involved in the earlier sponsorship scandal include Aoki Holdings, a clothing company that dressed Japan’s Olympic team, and Sun Arrow, which produced the Tokyo Olympic and Paralympic mascots named Miraitowa and Someity.

Takahashi, in custody since August, had tremendous influence over running the Olympics. The bribes he is alleged to have taken total more than $1.4 million.

“We continue to fully cooperate with this investigation,” Dentsu’s corporate communications office said in a statement.

Cerespo, an event company that Japanese reports said also was raided on suspicion of involvement in bid-rigging, did not have an immediate comment.

Tokyo prosecutors do not comment on such daily news developments. But Deputy Chief Prosecutor Hiroshi Morimoto told reporters recently that the investigation was continuing on the Olympics.

Speculation has been growing the burgeoning scandal may tarnish Japan’s bid for the 2030 Winter Games. The 2020 Games were postponed for a year because of the coronavirus pandemic. The International Olympic Committee has said it’s watching Japan’s investigation, stressing it had “every interest in the full clarification of this case.”