German show jumper Christian Ahlmann is ineligible to compete at the 2012 London Olympic Games, according to the International Olympic Committee.

An IOC rule introduced before the 2008 Olympic Games bans athletes from the next Olympic Games if they received a drug suspension of at least six months in the previous four-year period. “Should an athlete get caught doping in [2008] and then get a sanction of six months, he will not be eligible for the 2012 London Games,” said IOC spokeswoman Giselle Davies.

Ahlmann’s original four-month suspension from the Fédération Equestre Internationale was doubled to eight months after the German Federation appealed to the Court of Arbitration for Sport. Ahlmann’s horse, Cöster, tested positive for capsaicin after the team competition at the 2008 Olympic Games in Hong Kong.

Four other riders—show jumpers Denis Lynch, Bernardo Alves and Rodrigo Pessoa and U.S. dressage rider Courtney King-Dye—were suspended by the FEI for doping offenses at the 2008 Olympic Games in Hong Kong, but all those suspensions were for fewer than six months. The FEI banned Alves for 31⁄2 months and Lynch for three months after their horses tested positive for capsaicin. Pessoa was banned for 41⁄2 months after his horse tested positive for the pain reliever nonivamide. King-Dye was suspended for one month because her horse Mythilus tested positive for the anti-inflammatory medication, felbinac. She lost her 13th-place finish in individual dressage and the U.S. dressage team was disqualified after placing fourth.