Greek prosecutors have opened an investigation into how a lab blunder allowed Olympic champion Tyler Hamilton escape an alleged blood doping charge.
Hamilton has consistently denied doping allegations
The American tested positive for a blood transfusion after winning the Olympic time trial gold medal.
But the result of his B or second test was deemed "non-conclusive" after it was discovered the sample had been destroyed by being deep-frozen.
Prosecutors want to determine if the freezing was deliberate or negligent.
The American is also being investigated for failing another test for a blood transfusion during October's Tour of Spain.
He has always denied the doping allegations.