“Of course, we are not amused.” The International Olympic Committee president, Thomas Bach, invoked Queen Victoria this week when asked about the spiralling crisis surrounding allegations of corruption concerning Tokyo’s successful bid for the 2020 Olympic Games.

There is another saying in Bach’s native Germany – “wash me but don’t get me wet” – that rather seems to sum up the attitude of the Olympic family to a firestorm that began as a localised outbreak at the Monaco headquarters of the world governing body of athletics, has shifted to Japan and now threatens to spread to the IOC’s headquarters on the banks of Lake Geneva.

Questions that were supposed to have gone away after the Salt Lake City scandal over how the IOC conducts bidding for its most prestigious events have aligned alongside the Russian doping crisis and the panicky atmosphere surrounding the countdown to the Rio Olympics to create something of a perfect storm.

Since the Guardian revealed the Tokyo 2020 bid had made seven-figure payments to a company linked to the son of the disgraced former IAAF president Lamine Diack, already implicated in earlier corruption charges linked to Russian doping, Japanese officials have, day by day, been forced to reveal more information about the contract. The more they dig, the deeper the hole.

When the question was first put by the Guardian to the Japanese Olympic Committee – whose president and IOC member, Tsunekazu Takeda, was head of the bid and sits on the board of the organising committee – the response was that it was away on business for a week so would not be commenting.

The Tokyo 2020 organising committee, already beset by difficulties ranging from an embarrassing stadium design U-turn to a logo plagiarism row, said simply it had “no means of knowing these allegations”. Despite Takeda and other officials spanning the bid and the organising committee, a spokeswoman Hikariko Ono said: “We believe that the Games were awarded to Tokyo because the city presented the best bid.”

In three days of questioning from opposition MPs in the Japanese parliament the fog has slowly started to clear as they have probed the links between Diack, who stands accused by French prosecutors of accepting more than €1m for covering up positive drug tests, and Black Tidings, a Singaporean company. Diack was at the time president of the No1 sport in the Olympics and a key powerbroker among the IOC membership, particularly in Africa. Diack remains in France, having surrendered his passport, but has never publicly commented on the allegations.

It has now been established that the first payment, of $950,000, was made for a contract with Black Tidings that ran from 1 July to 30 September 2013 for consultation on lobbying activities. According to Takeda, the second contract worth $1.375m ran from 5 October to 30 November and included “analysis on bid winning factors”.

We are being asked to believe $1.375m was knowingly paid after the bid was won for what was described by Nobumoto Higuchi, the deputy chief executive of the now dissolved bidding committee, to Kyodo News as a 30-40 page document on how they did it. “It had a good deal of substance in it,” he said.

Japanese broadcasters had tracked down Ian Tan Tong Han, the registered owner of Black Tidings, to an apartment in Dakota Crescent in Singapore. Tan was said by Dick Pound’s Wada report to be a constant companion to Papa Massata Diack, Lamine’s son, since the pair met at the Beijing 2008 Games and so devoted to his friend that he named his son after him in 2014.

In the clip a man in his twenties emerges from an apartment that does not appear to be the sort of place from which multimillion dollar consultancy contracts are typically serviced. He says he is co-operating with the authorities. Hajo Seppelt, the fearless documentary maker who ignited the slow-burning Russian doping scandal, told the Guardian it appeared to be the same man who appeared in blurred form in his 2014 programme and was later identified by Nick Davies, a senior IAAF official, as Tan.

Another report, this time in the Singapore newspaper Today, said: “When this newspaper visited the flat yesterday, a woman who identified herself as Tan’s mother said that her son stays with her sometimes when he is not overseas for work. She added that Tan was at work but refused to comment further.”

We are asked to believe that a youthful sidekick for the former IAAF marketing consultant Papa Massata Diack, now holed up in Dakar with an Interpol wanted notice and denying all wrongdoing, was paid more than $2m for consultation work “including the planning of the bid; tutoring on presentation practice; advice for international lobbying communications; and services for information and media analysis”.

Claims first published in Le Monde in January about a spending spree on watches and other luxury items on the Champs Élysées by Papa Massata Diack have been connected to the revelations about the payments. The Japanese outlet Kyodo News reported this week that Diack’s son spent around €130,000 on high-end jewellery in Paris around the time of the first payment from Tokyo 2020, transactions that are believed to be under consideration by French prosecutors.

It was impossible not to be reminded of a 2008 email seen by the Guardian this year.

In it, Papa MassataDiack appeared to be in discussion with a Qatari contact over “parcels” to be delivered to six influential IOC members identified only by their initials at a time when it was bidding for the 2016 Olympics.

It is also hard to see how the Japanese marketing giant Dentsu, which has an all-encompassing deal to handle the IAAF’s marketing rights until 2029 under a contract negotiated by Diack and has a hugely powerful position in Japan, can avoid tough questions.

Athletic Management & Services, an outfit based in Lucerne in Switzerland that is partly staffed by executives who formerly worked for the controversial Fifa contractor Internation Sports & Leisure, was said by Pound’s report to be a service company for Dentsu.

Dentsu denies that AMS is a subsidiary but admits they have a “business relationship”. Pound’s report said Tan was retained as a consultant by AMS.

On its website it boasts of “a long-term relationship with the Japanese advertising giant, Dentsu” and says its role includes “successful delivery and commercialisation” of the world athletics championships and the FINA world aquatics championships – both Dentsu properties. Industry insiders say it has very few other clients.

Coincidentally, Takeda, who like others in the interlocking worlds of sports politics and business wears many hats, also heads the IOC marketing commission. Around the table of that commission also sits one Haruyuki Takahashi, a long-time friend of Sepp Blatter, who is a former senior Dentsu executive.

He was accused last year by the hospitality ticket agent Benny Alon, whose allegations helped bring down the former Fifa secretary general Jérôme Valcke, of asking him for €2m to give to Blatter. Blatter and Takahashi denied the claims.

As the Japanese parliamentary inquiry, which the prime minister, Shinzo Abe, has insisted must get to the bottom of the issue, and the French police investigation, so far admirably probing even in light of the nascent Paris bid for the 2024 Olympics, continue their work it must be hoped that the tangled web will unravel. “The reality at the time was that we couldn’t win without consulting power,” said Higuchi. Just what that consulting power bought them is just one of many questions hanging over the IOC at the end of one of its worst weeks since the height of the Salt Lake City scandal.

Bach, who will travel to Tokyo with his executive board, said: “We have all the instruments in place to fight against corruption but we are not immune from corruption. We do everything we can to address and to fight this evil.”

As a one-time protege of the Adidas scion and ISL founder, Horst Dassler, Bach is better schooled than most in the backroom deals and cynical real politik of modern sport. He must now prove his words will be borne out by actions.