World and Olympic 100m champion Justin Gatlin is facing a lifetime ban after confirmation that his B sample tested positive for testosterone.
Gatlin announced on Saturday that he had tested positive
The American announced on Saturday that he had failed a doping test in April.
And anti-doping chief Dick Pound and Gatlin's lawyer Cameron Myler told Five Live on Sunday that the 24-year-old's B sample also tested positive.
Gatlin's case is expected to be heard by the United States Anti-Doping Agency hearing next Monday.
"The B sample is positive, they've gone through that whole exercise," World Anti-Doping Agency (Wada) chairman Pound told Five Live.
If he can find somebody who did in fact spike it that's for them to prove
"What remains now is for the appropriate penalty to be handed out by the US Anti-Doping Agency and that will be reviewed by the IAAF, and by Wada if we're not satisfied that the right result has been achieved."
Gatlin also tested positive for an amphetamine in 2001 and Pound confirmed that if the World Anti-Doping Code is properly applied the American faces a life ban.
"(Gatlin) needs to be banned for up to life," said Pound.
"There may be some extenuating circumstances but if he just continues some sort of bland denial that will not help him when it comes to sentencing.
"If he can find somebody who did in fact spike it that's for them to prove, but short of something like that he faces a very serious problem."
Myler told Radio Five Live her client struggled to come to terms with the news when he was first told.
1982: Born in Brooklyn, Feb 10
2001: Wins US college 100m & 200m while at University of Tennessee
2001: Banned for two years for testing positive for an amphetamine
2002: IAAF reduces ban to one year
2002: Turns professional and begins working with coach Trevor Graham
2003: Wins US and world indoor 60m titles
2004: Wins 100m gold at Athens Olympics in 9.85secs
2005: Wins 100m & 200m gold at World Championships in Helsinki
2006: May 12 equals world record of 9.77secs in Doha
2006: July 29 announces he has tested positive for unusual levels of "testosterone or its precursors"
"He was in shock," said Myler. "Justin has not done anything, he has not taken anything, hasn't used anything and he certainly hasn't authorised anyone else to.
"He is finding it very difficult."
Gatlin's coach Trevor Graham has already said his athlete has been "sabotaged" and that he knows who is responsible.
But Pound said: "Bear in mind Trevor Graham is himself being investigated by the Grand Jury because a surprising number of his athletes have been found guilty of doping offences."
The IAAF on Monday confirmed that Graham himself could be banned for two years if Gatlin is found guilty of doping.
Myler added: "I heard of (Graham's) comments and read them in the press this morning - they are not authorised by us and we didn't know about them.
"Trevor's comments were not made with the knowledge or authorisation of either Justin or us. At this point we are trying to figure out what was the cause of the positive test."
Wada chairman Pound said that Gatlin's positive drugs test is proof that doping is widespread in athletics.
"It's an indication that there is still rampant drug use going on," said Pound.
"And it's not just in the middle of the pack or at the back of the pack, it's the leaders."
Pound did concede that small steps are being made by the sport in the USA to tackle doping in athletics.
"There certainly was in the past quite a lot of sweeping under the carpet and it's been a bone of contention between me and USA Track & Field (USATF) for a number of years," he said.
"This time at least USATF has come out and said this is a problem we acknowledge that there's a (positive) test and it's a very serious matter, so I think that there's some evolution but there's a long way to go too."