I think you are making my point for me. The "precisely" here is sarcastic. Is what a lip reader thinks someone else has said a primary source of evidence? Even worse when it is what they think someone is claiming someone else said together with the alleged offender seeming to deny it happened...
What are you wittering on about Walker for? The flakey Internet rumour is a lip reader telling us precisely what is was Maupay said to him in the middle of a football match.