Karlheinz Schreiber has repeatedly said that his Edmonton lawyer, Robert Hladun, received two approaches - one from Brian Mulroney, the other from Mulroney and his lawyer, asking for a statement from Schreiber attesting that no money ever passed between them.
Mulroney says it never happened.
What we need to hear is Robert Hladun's account. Ordinarily this sort of thing might be subject to a solicitor-client privilege, at least arguably, but not now that Schreiber has effectively waived privilege by discussing it publicly.
Schreiber has made the allegation. It's demonstrably damaging to Mulroney. Hladun can clear the air. If the ethics committee wants to clear Brian Mulroney, subpoena Robert Hladun and get his evidence on this on the record, under oath.
If Hladun denies Schreiber's account, then that should be one giant hole in the guy's credibility. If Hladun confirms Schreiber's account, that pulls the carpet right out from under Mulroney's.