Another day, another police raid on a global sports federation. And, in at least one way, this could be said to be bigger than Sepp Blatter.

The former president of world athletics has been placed under criminal investigation on suspicion of abetting cheats by taking money to cover up doping tests. For all the many scandals that have brought Fifa to its knees, no one has accused Blatter or his cronies of corrupting the game itself.

Dodgy bid processes? Backhanders on multi-million broadcast deals?

Our eyes have been opened to these seemingly everyday crimes within sports bodies, but nothing could be more serious than the charge of protecting, and profiteering from, cheats.

That is the nightmare threatening to engulf athletics with French prosecutors investigating whether Lamine Diack, the former International Association of Athletics Federations president, took €200,000 (S$306,000) to collude with the Russian federation over doping tests.

To think that it was only in August that (new IAAF president Sebastian) Coe pronounced: "The idea that my sport sat there either covering up wrongdoing or just being incompetent could not be wider of the mark."

Even at the time, it felt like a reckless thing to say. The sight of French gendarmes marching into the IAAF's headquarters in Monaco this week must have rocked even Coe's self-certainty.

"There is no job I have ever wanted to do more," Coe said of succeeding Diack as president of the IAAF in August. But he had already failed to recognise the scale of problems left by Diack, the man Coe calls "my spiritual president" and close friend.

Even before he took office, Coe had rashly attacked the whistle-blowing revelations by ARD, the German broadcaster. It claimed that the IAAF had failed to act on suspicious blood tests involving hundreds of athletes between 2001 and 2012.

True, caution was required because some of those suspicions were based on nothing more than anomalies. There was a danger of smearing athletes without proper evidence, with a furious Paula Radcliffe going public with her dismay about featuring on the list.

But it was clear all along that the programme had substance, and raised many serious allegations about IAAF governance that needed investigating.

The claim that a Russian official extorted €450,000 from Liliya Shobukhova, the London Marathon winner in 2011, to allow her to compete at the 2012 Olympics was particularly alarming. Now, it has led directly to the IAAF.

The ARD report prompted a World Anti-Doping Agency (Wada) investigation, led by Dick Pound. Evidence from that inquiry was passed to Interpol. French police have interviewed Diack and Habib Cisse, his adviser, while Gabriel Dolle, the IAAF's anti-doping director, is in custody.

We await the outcome of police inquiries, and Pound's report, which is due to be published next week. And we do so recalling something Coe said in August: "There is nothing in our history of competence and integrity in drug-testing that warrants this kind of attack."

It was reckless talk that has already damaged Coe's credibility. He should have declared the need for athletics to get to the bottom of such damaging allegations while protecting clean athletes.

Coe will argue that his defence of the sport was based on his certainty that athletics is cleaner than a decade ago, thanks to anti-doping improvements like the biological passport introduced in 2009.

But it was Pound, as a former president of Wada, who once warned that the greatest weakness in the doping war was not the cheats but those who protect them; corrupt federations trying to keep the business on the road. We have seen it in cycling - the UCI, the sport's governing body, was found to have given favourable treatment to Lance Armstrong and sought to contain, not confront, the problem.

Armstrong even gave the UCI money, though the leadership were never accused of pocketing funds.

According to sources in France, Diack is suspected of taking about €200,000 to cover up an as yet undetermined number of doping positives.

Even if authorities have proof of money changing hands, it remains to be seen if there is evidence of Diack being involved in tampering with tests, or deferring results, during his 16 years as president.

The IAAF insists that it is fully cooperating.

Coe was in Monaco on Tuesday and he is said to have told the police that he and the organisation will assist in any way possible. That is the least we may expect from the sport's leader who has sought to downplay the idea that athletics is in crisis. Police knocking at the door should have disabused him of that blithe complacency.

THE TIMES, LONDON