Football Association chairman Greg Clarke has been asked by an MPs' hearing into football governance to explain why allegations against Neil Warnock in 2014 were not followed up.
Allegations that Warnock, recently appointed as Cardiff manager, was "crooked" and was "ruining the game" were made by Crystal Palace midfielder Jason Puncheon on Twitter but quickly deleted.
The allegations were repeated at Westminster on Monday by Damian Collins, the chairman-elect of the Culture, Media and Sport Committee.
Collins, the Conservative MP for Folkstone and Hythe, was questioning Clarke about the governing body's attempts to investigate possible wrongdoing in the game.