The Badminton World Federation (BWF) has charged eight female Olympic badminton players with “not using one’s best efforts to win a match”.
Four pairs of players – two from South Korea, one from China and one from Indonesia – could be disciplined.
Spectators booed the two badminton matches played at Wembley Arena on Tuesday, in which the four accused pairs of players were appearing.
China’s Yu Yang and Wang Xiaoli and South Koreans Jung Kyung-Eun and Kim Ha-Na are among those facing charges.
The longest rally in their game lasted four shots, with match referee Thorsten Berg coming on to court at one point to warn the players. The players also appeared to deliberately serve into the net and hit the shuttlecock out of the court.
Both pairs were already through to the quarter-finals. Reports have suggested they both wanted to lose to secure an easier draw.
The unseeded South Koreans eventually won their match, meaning they would next play China’s Tian Qing and Zhao Yunlei.
The South Korean pair did not comment, but Yu Yang said she and Wang Xiaoli were saving energy for the knockout stages.
Meanwhile, China’s Olympic sports delegation launched an investigation into the alleged “deliberate losing” by its badminton players, saying it opposed any behavior violating “sporting spirit and morality”, as reported by state media.
A later match between South Korean third seeds Ha Jung-Eun and Kim Min-Jung and Indonesian pair Meiliana Juahari and Greysia Polii is also under scrutiny by the Badminton World Federation.
Both pairs of those teams had also already qualified for the knockout stages, with the winner of Group C to play Yu Yang and Wang Xiaoli and the Korean pairs to face each other if Kim Ha-Na and Kim Min-Jung lost.
At one point the referee, Thorsten Berg, again intervened and brandished a black card to disqualify the players. However, he then rescinded his decision following protests from the two teams.
Both teams appeared keen to lose and therefore not play the Chinese in the next round, but the Koreans eventually won by two sets to one.
A statement from the BWF confirmed that all four pairs would face charges of “not using one’s best efforts to win a match” and “conducting oneself in a manner that is clearly abusive or detrimental to the sport”.