Asbel Kiprop has suggested he tested positive for EPO because drug control officers tampered with his sample, having also demanded money from the Kenyan 1500m runner during the test.

Kiprop, a three-times world champion and 2008 Olympic gold medallist, said he would be “the last person to commit such an atrocious un-sports-like thing” as doping.

He also claimed he was told that if he confessed to taking drugs he would be made an ambassador of athletics’ governing body, the IAAF. “I have refused, as this is not only untrue but also a fraud,” he said. “I do not need absolution on the allegations.”

In a four-page statement, the 28-year-old said he been notified about a drugs test a day in advance, which is against World Anti-Doping Agency rules, and that two men had come to his house in Kenya on 27 November last year.

“After the doping control officers arrived at 7.50am, and after I had given them the urine sample, a DCO [the Guardian has chosen not to name the individual for legal reasons] asked for the first time in their visits if I could give them some money. He did not specify how much they needed. At 8.11am I forwarded to them money through his phone using M-Pesa. As a police officer I found it wise to send by M-Pesa for record.

“At that time I did not see the money as inducement or bribe for anything. I gave it in good faith thinking they may have some need known to them. In retrospect I now clearly see the money as having a relation with the sample collected on that date.”

Kiprop, who is the third fastest 1500m runner in history, also pointed out that if he had EPO in his system he could have chosen “to miss the collection without consequences” as Wada punishes athletes only for three missed tests.

He said: “I remain perplexed on how my innocent sample could turn positive on the only time when money was extorted from me. It is not beyond my suspicion that my sample turned positive because I might have remitted less money than I was expected to remit.”

Kiprop said he was “extremely shocked” when he was told in early February he had failed a drugs test. “I was, however, very confident the mistake alleging I doped would be noted and I would be cleared. [But] the nightmare has continued. I insist I am innocent even if I am forsaken.”

He also criticised how his positive test was leaked. “I was told the process of investigation and evaluating the question of whether or not there was any dope in my sample would be confidential. I am therefore surprised at how the handlers of the issue have let it out to the main media – to subject me to mob trial with a narrative designed to reflect me as guilty without my side of the story being reflected.”

An IAAF spokesperson said it was unable to comment and referred the Guardian to the Athletics Integrity Unit, which has so far not responded to Kiprop’s allegations.