The authorities confirmed they are investigating 21 athletes from eight different countries in relation to a blood doping scandal which broke when a series of raids were carried out around the Nordic World Ski Championships in Seefeld, Austria at the beginning of March.
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Nine people and five athletes, including Olympic skier Max Hauke, were detained at the time, as part of a joint operation between German and Austrian police dubbed "Operation Bloodletting".
In Munich, the state prosecutor confirmed that the scandal could have wider implications.
"The 21 athletes come from five different sports, of which three are winter sports," senior prosecutor Kai Gräber said at a press conference on Wednesday.
The athletes are suspected of having undergone a "three-digit number" of blood transfusions since 2011, Gräber said.
The transfusions were carried out in locations across the world, he added, including in Germany, Austria, Switzerland, South Korea and Hawaii.
At the centre of the scandal is Mark Schmidt, a 40-year-old doctor from the city of Erfurt in Eastern Germany, who was one of four people taken into custody earlier this month.
But Gräber confirmed on Wednesday that a fifth arrest had been made.
The person in question is alleged to have transported bags of blood and assisted athletes in doping. "We have here an exciting story with a lot of twists, and the final chapter has not yet been written," said Gräber.