London ? With Justin Gatlin preparing to defend himself on doping violations, the spotlight turned squarely on Trevor Graham, the track coach associated with at least a half-dozen athletes who have received drug suspensions.

The sport’s international governing body said Monday that Graham could face a two-year ban if Gatlin, the Olympic and world champion sprinter, is found guilty of a second doping infraction.

“Once we have enough evidence to prove it, then we have the power to prosecute him,” IAAF spokesman Nick Davies said.

The International Association of Athletics Federations would act only if evidence links Graham to any doping violations and the U.S. Anti-Doping Agency decides not to take action against him, Davies said.

The IAAF said it gave little credence to Graham’s claim that Gatlin was the victim of a massage therapist who rubbed testosterone cream on his legs without his knowledge.

“We have a strict liability rule that what’s in your body is your responsibility, so unless there was an independent witness who saw everything clearly, there really isn’t a possibility that there would be something in that,” Davies said.

Cameron Myler, Gatlin’s attorney, said Graham was “not speaking on behalf of Justin.”

Speaking by telephone from her office in New York, Myler said Gatlin voluntarily had withdrawn from competition until the doping issue was resolved.

She said her client’s case would be based “on the ‘exceptional circumstances’ clause of the World Anti-Doping code.”

That clause allows for a lesser penalty if it can be proved that the athlete was not responsible for the positive test. The exception is rarely granted.

“It’s a difficult standard, but it’s definitely something that we’re working toward,” Myler said.

“We’re trying to reconstruct what happened in Kansas, looking at who had access to Justin to cause the positive result. Justin didn’t do anything to cause this, and he didn’t authorize anyone to put anything on him that would have caused it.”

Gatlin said Saturday he had been informed by the USADA that he tested positive for testosterone or other steroids after the Kansas Relays in April. He said he never knowingly had taken banned substances.