Asafa Powell's physiotherapist on Wednesday hit back at claims from the Jamaican sprinter that he was to blame for a positive dope test, maintaining that he did not provide him or compatriot Sherone Simpson with banned drugs.
Powell and Simpson were among five Jamaican athletes who tested positive for performance enhancing drugs at the country's national trials last month and are currently under investigation in Italy for doping.
The revelations - and a separate positive test for US sprinter Tyson Gay - have cast a shadow over athletics, just a month before from the sport's world championships in Moscow.
Powell and Simpson's agent, Paul Doyle, on Tuesday pointed the finger at the athletes' physio Chris Xuereb, suggesting that contaminated food supplements were to blame. (Read: Powell's agent takes blame over suspected trainer)
But Xuereb, who is also under investigation in Italy, maintained that he had done nothing wrong and the athletes were looking to make him a scapegoat.
Xuereb said in an emailed statement to a number of media organisations that he began working with the Jamaican pair in May 2013 as they recovered from injury, providing massage therapy and nutritional advice.
He said he worked "extremely hard" to help their recovery, adding: "Most importantly, I did not provide any banned or illegal substances to Asafa Powell or Sherone Simpson."
Xuereb accepted that he recommended vitamins to the runners but maintained that they were all bought over-the-counter at reputable nutritional stores and were major brands.
All the vitamins, which were recommended by the athletes' agent and shown to their coach, were found to be legal by the Italian police, who raided the athletes' base and questioned Xuereb for several hours earlier this week, he added.
Xuereb, who said he was not arrested and cooperated fully with the Italian authorities, suggested that Powell and Simpson, who tested positive for a banned stimulant, may have been taking other supplements that he was not aware of.
"Both athletes are clearly looking for a scapegoat," he said in the statement, which was quoted on the Toronto Star website thestar.com, among others.
"I am confident, and I have also spoken to researchers and the Police, that I have done nothing wrong."
Xuereb said he had no dealings with the three other Jamaicans who tested positive at last month's trial and said it was "time the athletes took responsibility for their doping" instead of blaming others.
"I am extremely disappointed that these athletes have chosen to blame me for their own violations," he added.
"WADA (the World Anti-Doping Agency) and the public needs to stop accepting these stories and hold these athletes accountable."
Powell, a 4x100m relay gold medallist at the 2008 Olympics in Beijing, is one of the four fastest men over 100m in history.
Simpson won gold for Jamaica in the 4x100m relay at the Athens Olympics in 2004 and silver in the event last year in London. She also won 100m silver in Beijing.