THE WORLD'S leading anti-doping prosecutor, responsible for the downfall of Lance Armstrong and Marion Jones, insists ignorance plays no part in Essendon players being proven guilty in regards to their 2012 supplements program.

Richard Young, an American sports lawyer based in Colorado, will be central to the decision making in ASADA's investigation into the supplement programs at AFL and NRL clubs.

"If an anti-doping organisation, such as ASADA, is able to demonstrate that an athlete used a prohibited substance then that is a strict liability violation," Young said.

"Whether the athlete thought they were getting something else or whether they thought the substance was legal or not.

"That is how the rules have played out consistently on all sorts of stages because that is what the anti-doping code says."

Young's integrity with anti-doping examination is unrivalled, and his knowledge of the WADA code comes first-hand.

He was the principal draftsman of the code in 2003, and for its modification in 2009.

Young first came in contact with ASADA officials "two to three months ago", before they flew to Colorado in late April to present him with documents.

ASADA met him at his base in Colorado Springs before consulting their United States counterparts, USADA, through CEO Travis Tygart and lawyer Bill Bock.

Young was briefed on the ongoing ASADA investigations into the Essendon Football Club and Cronulla Sharks NRL club.

"I know what I've learned from ASADA, the documents they've provided and I've reviewed," Young said.

"I've talked to them about what I'd recommend they do. I'll be involved in the decision making process as we go down the road.

"I think it means that ASADA takes their job very seriously, they understand what they're dealing with is complicated. I'm flattered they have come to me with my experience to help them."

Young was consulted for the Lance Armstrong case which broke open last year, and was central to the BALCO investigation which included sprinter Marion Jones being ordered to hand back Olympic medals.

He refused to give an indication into the timeframe of ASADA's investigation into the Essendon Football Club.

"You try to work as quickly as you can. There's a lot of moving pieces and parts," he said.

"It depends on how they all come together. The Armstrong case took a long time and then pieces started to fall and when they fell they fell together quickly."

Young will continue to consult ASADA from Colorado but refused to rule out the possibility of being flown to Australia to be closer to fellow investigators.