Sydney:Australia's sports doping agency has cleared champion swimmer Ian Thorpe of doping charges fueled in March when urine tests showed elevated levels of two banned substances.
"The evidence available does not indicate the use of performance enhancing substances by Mr Thorpe," the Australian Sports Anti-Doping Authroity said in a statement.
"He has no case to answer."
Thorpe welcomed the ASADA decision.
"My reputation as a fair competitor in swimming is the thing I value most," he said in a statement. "I have always been, and remain, a strong supporter of anti-doping testing.
"I firmly believe drugs have no place in sport. I took my obligations to comply with the anti-doping codes very seriously and prided myself on this."
Thorpe became embroiled in the doping investigation when a urine sample taken in May, 2006 showed elevated levels of testosterone and epitestosterone.
The French newspaper L'equipe reported the test results in March this year at the time of the swimming world championships in Melbourne, sparking a wider inquiry.
ASADA had, by that time, decided not to pursue a doping investigation against the retired Thorpe because it believed the substances were naturally-occuring. It was forced to revisit that stance when swimming's international body, FINA, appealed the decision to the Court of Arbitration for Sport.
Thorpe, 24, set out immediately to clear his name and earlier this month provided medical evidence to ASADA which, he said, proved the high levels of testosterone and epitestosterone shown in last year's test were naturally occcuring.
"ASADA's comprehensive review included an examination of the athlete's recent test history and athlete-supplied medical documentation in line with the World Anti-Doping Agency code," ASADA said.
Officials said ASADA got expert medical and scientific opinion from the Australian Sports Drug Medical Advisory Committee (ASDMAC); the World Anti-Doping Agency (WADA) accredited laboratories in Sydney, Australia and Montreal, Canada; and the ANZAC Research Institute in Sydney.
"Experts from these internationally respected organisations were unanimous in their opinion that the evidence available does not indicate the use of performance enhancing substances by the athlete," the ASADA statement said.
"While the matter has taken some time to resolve, ASADA was absolutely determined to ensure that the results of our examination would leave no room for doubt."
Thorpe's manager, David Flaskas, hailed the ASADA decision as a vindication.
"We are pleased with the results from the ASADA investigation, which found there was no case to answer and that ASADA consider the matter closed," he said.
"We were also pleased that ASADA consulted independent experts from internationally respected organisations and they were unanimous in their opinion that there was no evidence of the use of performance enhancing substances by Ian Thorpe.
"We always believed this would be the outcome and Ian's reputation as a fair competitor would be affirmed,"
Thorpe, who won five Olympic and 11 world championship titles in an illustrious career, retired from competitive swimming last November.