Controversial sports scientist Stephen Dank is reportedly set to sue ASADA and its chief executive Ben McDevitt for defamation.
Dank told Fox Sports News of his plan to launch legal action on Thursday.
It comes a day after McDevitt publicly called on Dank to produce any records relating to Essendon's "utterly disgraceful" 2012 supplements program, of which he was the alleged architect.
Dank, according to the report, claimed intricate records were kept and given to both ASADA and the AFL.
The AFL anti-doping tribunal on Tuesday cleared 34 current and former Essendon players of taking banned substance Thymosin beta-4 - a decision ASADA is considering appealing.
Dank is also before the tribunal in connection with the club's supplements program, with a verdict to be delivered after Easter.
Dank declined to be interviewed by ASADA as part of its investigation and has insisted the players were never given any banned substance.
