TOKYO, Nov. 25 (Xinhua) -- The head office of Japanese advertising firm Dentsu Inc. was raided on Friday by Tokyo prosecutors and Japan's Fair Trade Commission over possible bid rigging connected to the Tokyo Olympic Games held last year.

Along with the advertising giant, the residence of a senior official at the Tokyo Olympics organizing committee was also searched, and Cerespo Co., an event production company, has also been implicated.

The raids are the latest in a string of scandals connected to the Games, with the latest searches by authorities conducted on suspicion of unfair restraint of trade.

They suspect the awarding of contracts in open bids held for the rights to arrange 26 test events was rigged. The contracts were "won" by Dentsu, eight companies and a consortium.

Informed sources said the total value of the contracts was worth more than 500 million yen (3.6 million U.S. dollars), with individual contracts valued between 4 million yen (28,800 U.S. dollars) and 60 million yen (433,000 U.S. dollars).

The latest search follows another advertising agency ADK Holdings Inc. telling the Japan Fair Trade Commission it had been a participant in the bid rigging, with the agency hoping its admission would mean a lesser punishment from authorities.

With the Tokyo Games held a year late due to the global coronavirus pandemic, continued revelations of a string of scandals connected to one of the world's largest sporting events has tarnished the image of the host city and the firms and individuals potentially involved.

This has been punctuated by yet another investigation launched recently into a scandal related to allegations of bribes.