And on Sunday, Fairfax Media reported Essendon players were allegedly used as virtual human guinea pigs, being administered AOD-9604 at levels that far exceeded its clinical trials.
Fairfax Media also revealed the Australian Sports Anti-Doping Authority (ASADA) is examining whether the performances of players using the drug were measured against teammates who had not taken the drugs.
Investigators are also trying to establish whether those results were passed on to external parties, the report said.
In a statement to Fairfax Media, the Bombers said they had no knowledge of any such "clinical trial" and "if this is found to be true, it is deeply distressing and disturbing, and goes to the heart of what may have been perpetrated at our club."
"We are in the hands of ASADA, and we continue to support our players during this process and we have brought in independent medical and pharmacological advice, which has provided comfort to the club about the safety of our players.
"We have been limited in what we can comment on, and more than anything else, we want the ASADA investigation to be completed. There is information we still do not have as a club and we are looking to the ASADA investigation to uncover the full extent of what happened at the club."
AFL deputy chief Gillon McLachlan said in a press release on Sunday the League would not comment on "claims and speculation" related to the case "out of respect" for the ongoing ASADA/AFL investigation.
"We understand the intense interest in the matter, but the integrity of the process must be respected," he said.
"This is a matter involving complex factual and legal issues. Given this complexity, it is not appropriate to intervene and pre-empt the outcome of the investigation.
"Although frustrating, I urge everyone to remain patient and to allow the investigators to do their work and to reach their conclusions based on all the evidence available.
"We share everyone's desire to have the ASADA inquiries completed as soon as possible to provide clarity around a range of issues for the Essendon Football Club, its players and the wider competition. We remain committed to this happening in August.
"The AFL is in constant contact with the key parties involved and we are closely monitoring progress.
"In the meantime, as we have consistently stated, the AFL will not provide a running commentary."