The Oscar Pistorius row was reignited on Wednesday amid fresh allegations by the South African team that athletes were changing blades between races.
The International Paralympic Committee (IPC) received a letter on Tuesday from the South African team claiming competitors had been breaking rules by altering prosthetic legs between qualifiers and finals.
Blades are measured between races and it is illegal under Paralympic rules to switch blades during a competition.
Pistorius sparked controversy with angry comments he made after losing out on gold in the 200 metres, claiming Brazilian Alan Oliveira's use of longer blades gave him an unfair advantage.
Today Craig Spence from the IPC said: "When we put that allegation to the coaches there was a look of shock to be honest, because running on different size prostheses or swapping them for races is extremely difficult to do for an athlete.
"There is no evidence that any athlete competed on different size running blades.
"Unless the South Africans can come to us with some evidence that proves otherwise, it's something that we won't continue investigating."