Defending Olympic 50K race walk champion Alex Schwazer has been caught doping and will miss the London Games.

The Italian Olympic Committee says Schwazer has tested positive for doping and has been removed from the team. Earlier Monday, the team said an unidentified athlete had failed a doping test before arriving in London.

The 28-year-old Schwazer was due to defend his 2008 Olympic title in the 50-kilometer walk on Sunday.

Schwazer won gold at the Beijing Games in an Olympic record time of 3 hours, 37 minutes, 9 seconds.