Lord Coe has been accused of misleading MPs about how much he knew about the drugs scandal that has shaken athletics to its core.
The double Olympic champion and organiser of the London 2012 Games has always insisted he has been unaware of the full extent of corruption in his sport that allowed stars to cover up their doping shame.
But an email sent to Lord Coe reveals he received detailed allegations about a Russian marathon champion asked to pay £360,000 to senior athletics officials to have her drugs offences covered up.
The runner, Liliya Shobukhova, was then allowed to compete at the London Olympics in 2012.
Lord Coe, now the president of the International Association of Athletic Federations, received the email outlining the scandal in August 2014.
Four months later, the story became public when it was aired in a German TV documentary in December 2014.
Despite this, Lord Coe told MPs at a Parliamentary Select Committee in December 2015 that: "We were not aware - I was certainly not aware - of the specific allegations that has been made around the corruption of anti doping processes in Russia."
The new evidence was uncovered by the Daily Mail in a joint-investigation with BBC Panorama.
On Thursday night, after the existence of the damning email was revealed by MailOnline and the BBC, a spokesman for Lord Coe admitted he had received the message but failed to open it and simply forwarded it to ethics officials at the IAAF.
The email had been sent by London Marathon boss Dave Bedford when Coe was vice president of the IAAF.
On Thursday a spokeswoman for Coe claimed he simply did not open the email. "The worst you can accuse him of is a lack of curiosity," insisted Jackie Brock-Doyle.
She added: "Seb has never denied hearing rumours about corruption. In fact, he has said on many occasions that when alerted to rumours he asked people to pass them on to the Ethics Commission to be investigated.
"He did receive an email from Dave Bedford that said 'the attachments relate to an issue that is being investigated by the IAAF EC (Michael Beloff)'.
"This was enough for Seb Coe to forward the email to the Ethic Commission. He did not feel it was necessary to read the attachments. You may think this shows a lack of curiosity. He, and we, would argue that it shows a full duty of care. Ensuring the right people in the right place were aware of allegations and were investigating them."
When Coe appeared before MPs in December 2015, he said he did not know of the extent of the corruption in his sport until the allegations were aired in a German television documentary in December 2014.
He was asked by Labour MP Ian Lucas why the IAAF had not tackled the Russian doping scandal sooner when he had 'such a prominent role in the organisation', Coe replied: 'We were not aware - I was certainly not aware - of the specific allegations that had been made around the corruption of anti-doping processes in Russia.'
During an interview with ITN in November 2015, Coe was asked how it could be that he knew so little of what was going on. "These allegations are truly shocking," he said. "The allegations that corruption has taken place in our organisation are truly shocking. And no I did not know the basis of those allegations." To Channel 4's Jon Snow he said: "Those allegations have come as a shock to all of us."
On Thursday night Tory MP Damian Collins said that Coe's position as president of the IAAF will be 'impossible' unless he can provide a 'robust explanation'.
"On the evidence about doping in Russia, I think this is really significant information - that he was sent the detailed allegations four months before the evidence became public and yet denied any knowledge," said Collins.
"To the Select Committee he made it clear he had no specific knowledge of the allegations. That clearly wasn't true. His response was misleading to the Select Committee. I think he needs to make a public statement what he knew and what he did with the information."
Over the past two years athletics has been left stunned by a string of doping scandals which suggested that officials at the top of the sport conspired with star athletes to hush up the results of positive drug tests.
The blackmail plot allegedly orchestrated by officials at the top of Coe's organisation enabled Russian distance running star Shobukhova to compete illegally in the 2012 Olympics.
Lord Coe, who became IAAF president in 2015, has always insisted he was unaware of full scale of the scandal. But critics have always insisted that he must have known more than he has publicly admitted to.
Mr Bedford sent the email four months after he helped Shubokhova's agent send a written complaint to the IAAF Ethic Commission.
In the August he then sent the complaint to Coe, at the time the vice-president of the IAAF.
Within the contents of the email is also the implication that Papa Massata Diack, regarded now as one of the most controversial men in world sport, was involved in the blackmail scheme.
Papa Diack is the son of former president Lamine Diack, who is now under house arrest in France having been accused by French prosecutors of allegedly extorting more than a million Euros.
Papa Diack, currently hiding out in his native Senegal, is also wanted by the French authorities.
After the German documentary in December 2014, Papa Diack suspended himself from IAAF activity having worked for the organisation as a marketing consultant. In January 2016 he was banned for life from athletics.