Victo Conte, convicted owner of the now-defunct BALCO laboratory that was at the centre of a global steroid scandal, has said that the drug-testing programme at the 2012 Olympics was irrelevant.
"It's basically propaganda to come out and say this is the most expensively-tested Games ever and 'we're doing 6,000 tests'," Conte was quoted as telling The Times newspaper.
"You have to put your hook and line in the water when the fish are biting and that was nine months ago. Is it easy to use drugs and benefit during (the) Olympics? Yes."
The British newspaper also quoted Conte as estimating that "60% of athletes at the Games were on drugs".
Scientists have been working around the clock at a specially equipped anti-doping laboratory on the outskirts of London analysing more than 6,000 urine and blood samples during the Games.
Any of the 10,000-plus competitors can be required to test anytime, anywhere - trackside, poolside, in the athletes' village or in private houses - and several have already been thrown out of the Olympics for doping.
Conte's BALCO laboratory in San Francisco supplied drugs to leading athletes including Britain's Dwain Chambers who was banned for two years after testing positive for the designer steroid THG in 2003.
Chambers was picked for the London Games after becoming eligible for selection in May when the British Olympic Association's policy of lifetime Olympic bans for drug cheats was overturned by the Court of Arbitration for Sport.
Conte was sentenced in 2005 to spend four months in prison and another four on house arrest.
A spokesman for the IOC said it was a bit "like a poacher criticising a gamekeeper".
"If he has information, we'd love to hear it," he added.
"We really have to give the athletes the benefit of the doubt here.
"Where there's evidence, where we've done testing and catch them, and they're cheats, let's kick them out, but while they're doing great things, let's support them."