The Canadian at the centre of track-and-field doping accusations was a long-time employee of a Toronto sports medicine clinic operated by Dr. Anthony Galea, who pleaded guilty in 2011 to importing "misbranded" drugs, including human growth hormone, into the United States.
After two top Jamaican sprinters, Asafa Powell and Sherone Simpson, acknowledged that they had tested positive for a banned stimulant, Mr. Powell's agent blamed the test result on Chris Xuereb, who has been described as an assistant physiotherapist and who worked off and on for several years at the Institute of Sports Medicine and Wellness Centre in Toronto.
Mr. Xuereb denied Wednesday that he is to blame, and suggested the athletes are using him as a "scapegoat" for their own doping.
The west-end Toronto clinic is operated by Dr. Galea, a celebrated sports physician whose past clients have included golfer Tiger Woods and Canadian sprinter Donovan Bailey.
In a statement, Mr. Powell has confirmed that a urine sample he gave last month at the Jamaican National Trials tested positive for oxilofrine, a banned stimulant. But he said he did not knowingly take a supplement containing an illegal substance. "My fault here … is not cheating but instead not being more vigilant."
The agent for both track stars, Paul Doyle, said that Mr. Xuereb provided supplements that caused both sprinters to fail their drug tests.
In a response emailed to the Reuters news agency, Mr. Xuereb denied giving the Jamaican sprinters performance-enhancing drugs, saying "it is time the athletes took responsibility for their doping instead of looking around for a scapegoat." He said that he had provided massage therapy and nutritional help for the athletes, but never any banned or illegal substances.
"It is obvious that these athletes were taking additional supplements that were not discussed or known to me," he added.
According to a spokeswoman for the Ontario College of Physiotherapists, Mr. Xuereb isn't even qualified to design a physiotherapy treatment plan in Ontario.
He is not a doctor in Ontario. He is not registered as a chiropractor in Ontario. He is not a registered massage therapist in Ontario. He is not registered with the province's college of physiotherapists, the self-regulating body that ensures people who hold themselves out as physiotherapists have passed the necessary competency test and have at least an undergraduate degree. (The college allows less qualified practitioners to describe themselves as "assistant physiotherapists" as long as they are supporting a registered physiotherapist.)
When the test results were released, both sprinters and Mr. Xuereb were in the northern Italian town of Lignano Sabbiadoro, where they have a training base. Police raided their rooms, seizing supplements and other materials. According to Mr. Powell's publicist, Tara Playfair-Scott, police took Mr. Xuereb for questioning.
As for how Mr. Xuereb connected with the track stars – who have both led Jamaica to Olympic gold medals in the 4 x 100 relay – a Toronto-area chiropractor who occasionally works out of Dr. Galea's clinic apparently holds the answer.
The chiropractor, Carmine Stillo, confirmed through a spokesman for Athletics Canada that he referred Mr. Xuereb to the sprinters' agent when they said they needed a massage therapist on short notice. The chiropractor told the sprinters' agent "that Mr. Xuereb could be an option but that he had absolutely zero professional designations or credentials," said Mathieu Gentès, the Athletics Canada spokesman.
"Mr. Stillo told Mr. Doyle that he could use [Mr. Xuereb] at his own risk, but that definitely he had 'good hands' … which meant that Mr. Xuereb could join the group on this trip to help Mr. Powell deal with a chronic hamstring soft tissue issue."
Mr. Powell also has a history with Dr. Galea's clinic. Dr. Galea treated Mr. Powell's hamstring about a year ago with an experimental, but legal, healing procedure known as PRP, or platelet-rich plasma therapy, Mr. Greenspan said.
It was four years ago that Dr. Galea and his clinic became the focus of a U.S. law-enforcement investigation when his assistant, Mary Anne Catalano, was pulled over by a curious border guard near Niagara Falls.
Ms. Catalano admitted that she was transporting misbranded drugs, including the banned human growth hormone, to treat professional athletes. When Dr. Galea pleaded guilty in 2011 and avoided a jail sentence, he admitted that he instructed Ms. Catalano to lie to border guards about the true purpose of her trip, and that the drugs had been purposely disguised.
But U.S. prosecutors acknowledged that there was no evidence the doctor was trying to help athletes enhance their performance through doping – rather he was helping them heal with unapproved methods.
Mr. Xuereb was fired from Dr. Galea's clinic three years ago after he allegedly provided advice to patients that he wasn't qualified to give, said Brian Greenspan, a lawyer for Dr. Galea. In a telephone interview, Mr. Greenspan also alleged that Mr. Xuereb had been telling prospective employers that he was a relative of Dr. Galea, a claim that the lawyer called false.
"The only thing they have in common is their Maltese heritage," Mr. Greenspan said.