Regensdorf, Switzerland ? Olympic time-trial champion Tyler Hamilton declared his innocence Tuesday after his pro cycling team said he was being investigated for possible blood doping and could be stripped of his gold medal.

Hamilton said he would “fight this until I don’t have a euro left in my pocket.”

Tests at the Athens Olympics on Aug. 19 and at the Spanish Vuelta on Sept. 11 showed evidence of blood from another person, cycling’s governing body said, according to a spokesman for Hamilton’s team, Phonak. Follow-up tests were scheduled for later Tuesday.

Phonak spokesman Georges Luedinger said Hamilton denied having a transfusion — which can boost an athlete’s performance by increasing the amount of oxygen-transporting red blood cells in his system.

“Tyler told us he did nothing,” Luedinger said.

Hamilton’s gold was one of four medals won by American cyclists at the Athens Games — the team’s best showing since winning nine at the boycotted 1984 Los Angeles Olympics. Hamilton was the only American cyclist to win a gold medal in Athens, and he called that victory “the highlight of my career, by far.”

If found guilty of a violation at the Olympics, Hamilton would lose his gold. Three athletes had gold medals revoked for doping during the Aug. 13-29 games.

“I am 100 percent innocent,” Hamilton said.

Former world champion Oscar Camenzind was fired by Phonak and announced his retirement after testing positive for the performance-enhancing substance EPO shortly before the Olympics.

A record 24 athletes — none American — from various sports were cited for drug-test violations at the Athens Olympics.