The IAAF has dropped an investigation into the awarding of hosting rights for the 2017 and 2019 World Championships, citing a lack of evidence behind claims that Qatari officials had attempted to bribe delegates.
Qatar's capital city Doha was beaten to the award of the 2017 event by London, but is due to stage the championships two years later after holding off competition from Barcelona and Eugene - which will serve as host in 2021.
However, UK Athletics chairman Ed Warner raised concerns earlier this year about the process, revealing to the BBC that an unnamed IAAF official had suggested that IAAF Council members had been offered "brown envelopes containing cash" by the Qatari delegation in return for votes.
It has since been confirmed that the official in question was IAAF president Sebastian Coe, then serving as vice-president.
A statement from the IAAF Ethics Board read: "In response to enquiries made of him by the Board, Lord Coe has, however stated that he has no recollection of hearing such a rumour or therefore of communicating it to Mr Warner.
"In the same response to the Ethics Board, Lord Coe suggested that the Board also contact another person who was present with Lord Coe in Monaco on the occasion of the award of the 2017 World Championships to check his recollection.
"Upon enquiries of that person by the Board, he also stated that he had no recollection of witnessing or hearing any rumours of the kind referred to above."
It continued: "As a result of its preliminary investigations, and noting that there is no documentary evidence to corroborate Mr Warner's recollection, the Ethics Board does not consider that it has sufficient evidence at present to open, under its procedural rules, a formal investigation."