Prosecutors in Schwazer's hometown of Bolzano on Wednesday named five people who have been placed under investigation in the case. They are Schwazer's former coach Michele Didoni, Italian athletics federation medical director Giuseppe Fischetto, federation physician Pierluigi Fiorella, federation secretary Rita Bottiglieri and equestrian athlete Karl Wechselberger.
The five are accused of being aware of Schwazer's doping before he tested positive and failing to report it.
On Tuesday, authorities raided the offices of Italy's Olympic committee and athletics federation as part of the Bolzano inquiry. Schwazer was banned by the Italian Olympic Committee for 3 1-2 years in April.
Schwazer, who won the 50-kilometer walk at the 2008 Beijing Games, was excluded from last year's London Olympics after testing positive for EPO before the games. Prosecutors now believe coaches and physicians knew that Schwazer was doping long before he tested positive, possibly stretching back to Beijing.