Fresh evidence has emerged confirming reports that some Essendon players were given an unknown supplement sourced from Mexico, with the club backing away from its claim on Thursday that this did not occur.

Multiple sources have today confirmed that evidence collected by ASADA includes information that the substance given to some Essendon players was sourced in Mexico. This includes an interview investigators conducted with the muscular dystrophy patient who was given the supplement overseas and brought it to Australia.

Fairfax Media has further confirmed that Essendon is still unable to state with certainty what was in the supplement, although the club believes it most likely contained a mixture of safe amino acids.

Today, Fairfax Media published comments that Essendon lawyer Tony Hargreaves made on Thursday and which challenged earlier reports that some players had been given an unknown supplement sourced in Mexico from a man with a muscle wasting disease.

Mr Hargreaves said he had made his Thursday comments after he had spoken to the patient in question and had been told that supplements were sourced from a neurosurgeon in the United States.