Conflicting versions of what was said in the February 4 call have been detailed to the Australian Sports Anti-Doping Authority (ASADA), the Herald Sun reports.
Demetriou has denied any wrongdoing.
According to the paper, Demetriou and Evans allegedly talked about whether Bombers players had used banned substances.
AFL spokesman James Tonkin said on Wednesday night it was understood the claim was made by a particular witness in an interview with ASADA.
However, he said the allegations, which were disputed and discredited by other witnesses, were examined by ASADA and were "completely untrue".
According to the Herald Sun report, ASADA has been told the Demetriou call was made during an emergency meeting at Evans' Hawthorn home.
Others present at the gathering were Essendon coach James Hird, club doctor Bruce Reid, football boss Danny Corcoran and former chief executive Ian Robson.
