The International Equestrian Federation is investigating a second member of its president's family for alleged horse doping.
The governing body said Friday that Princess Haya of Jordan will step aside from her presidential duties when it considers the case against Sheik Hamdan bin Mohammed Al Maktoum, the son of her husband, Sheik Mohammed bin Rashid al Maktoum.
Sheik Hamdan rode his horse Eo Fawati in a 74 1/2-mile endurance race at Bahrain in January. The horse tested positive for metabolites of the anabolic steroid stanozolol.
Sheik Mohammed, the ruler of Dubai, rode his horse, Tahhan, when it tested positive for stanozolol metabolites in Bahrain. It also had traces of the banned substance guanabenz in Bahrain and after racing in Dubai in February.
Both men's cases are expected to go before the FEI's seven-member tribunal, which can suspend riders from endurance races.
As a member of the International Olympic Committee, Princess Haya informed the organization about the cases. Endurance racing is not an Olympic discipline.
Since becoming FEI president in 2006, the princess has campaigned to clean up equestrian's doping and medication problems.
She publicized details when six horses failed doping tests at last year's Beijing Olympics, and has commissioned IOC adviser Arne Ljungqvist to lead a review of the sport's methods of treating horses and educating riders. His report is due in the next few months.