The International Equestrian Federation (FEI) is urging anyone with information about alleged doping by German national riders to contact the investigation they have set up.

The FEI set up an ethics panel to look into the actions of German riders after Marco Kutscher claimed he had used unregistered medication on his horse at the 2008 Olympics.

Then in an interview with a German newspaper, on 24 May, German number one Ludger Beerbaum admitted using illegal practices in his horses.

The German federation reacted by dissolving all its national teams and on Friday (29 May) the FEI announced it was passing on the probe to the professional investigators Quest.

The FEI says it wants to know whether rules have been broken, is so by whom and whether this has affected any Olympic medals.

In a statement the FEI said: “The panel is of the opinion that there may have been breaches of FEI rules by riders, team officials and national federation representatives. It concludes that it should carry out a detailed investigation in order to make specific recommendations to the FEI president on these matters.”

The FEI asks anyone with information to contact Quest in confidence on 0044 20 7224 4004.