Eight women badminton players at the Olympics were charged by the sport's governing body on Wednesday with "not using one's best efforts to win a match" after two fixtures ended in controversy.
Four pairs in the women's doubles competition - one from China, one from Indonesia and two from South Korea - could be disciplined after the Badminton World Federation (BWF) took action.
A disciplinary hearing will be held later on Wednesday with a decision announced in due course.
At present all four pairs are included in the order of play with their quarter-finals scheduled for Wednesday evening.
The players in the two matches concerned were booed off court by angry spectators at Wembley Arena in London on Tuesday after they appeared to deliberately serve into the net, or hit the shuttlecock long or wide.
They were allegedly attempting to manipulate the final standings in the first-round group stage, with two pairs who had already qualified apparently wanting to lose to secure an easier draw in the next round.
The Group A match between the powerful Chinese pairing of Yu Yang and Wang Xiaoli and unseeded South Korean pair Jung Kyung and Kim Ha Na came under scrutiny by the BWF after the Chinese lost heavily.
There were no rallies of more than four shots in the match.
Their defeat meant Yu and Wang avoided playing fellow Chinese pair Tian Qing and Zhao Yunlei, who had finished second in Group D.
Yu said after the match: "We've already qualified, so why would we waste energy? It's not necessary to go out hard again when the knockout rounds are tomorrow."
A later Group C match in which South Korean third seeds Ha Jung-Eun and Kim Min-Jung beat Indonesian pair Meiliana Juahari and Polii Greysia is also being investigated by the governing body.
Tournament referee Torsten Berg came on to court during that match to warn the players about their conduct and was thought to have shown a black card -- meaning a dismissal -- but it was apparently rescinded.
Berg said after the match: "We have looked seriously into the case and as referee I have taken a decision and made a report to the BWF which will be known in due course."
Before the charges were laid, ex-Olympic silver medallist Nathan Robertson of Britain urged badminton chiefs to take action against matches being thrown after the furore at the London Games.
"It's obviously embarrassing and needs to be stopped," said Robertson. "Throwing of matches has happened many times before. I've been in matches myself where it's happened.
"But it's particularly embarrassing that it should happen in an Olympics. It's time the BWF took a strong stand. And maybe the IOC will consider whether this is in breach of the Olympic code of fair play."