The Badminton World Federation has charged eight female Olympic doubles players from three Asian countries 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.
Meanwhile, Team GB's gold medal hopes on day five of the Games lie mainly with rowers Helen Glover and Heather Stanning, and cyclist Bradley Wiggins.
And America's Michael Phelps has won a record 19th Olympic medal.
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 said she and Wang 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 behaviour 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.