In May 2007, several former riders admitted using banned substances (including EPO) while riding for the team in the mid 1990s, including Erik Zabel, Rolf Aldag, Brian Holm, Bjarne Riis, Bert Dietz, Udo Bölts and Christian Henn including the seasons in which Riis and Ullrich won the Tour de France. Team doctors Andreas Schmid and Lothar Heinrich also confessed to participating and administering banned substances. The latter was Team Telekom's sporting director until May 3, 2007 when he was suspended following allegations published in former team member Jef d'Hont's book.