NDP Leader Thomas Mulcair says top Conservative Party fundraiser Sen. Irving Gerstein “should have been thrown under the bus” after he was named in the RCMP documents on the Nigel Wright-Mike Duffy deal.

Mulcair’s comments came hours after he and Liberal Leader Justin Trudeau hammered Prime Minister Stephen Harper in question period Wednesday over why has not dismissed Gerstein and Sen. Carolyn Stewart Olsen after they were named in an RCMP affidavit made public last week.

Lead investigator RCMP Cpl. Greg Horton filed the affidavit in order to obtain more information for his investigation into the $90,000 cheque Wright eventually wrote to cover Duffy’s ineligible expense claims.

“Gerstein was making the same deal with Mike Duffy for a lesser amount, for $32,000 he thought at the time. When it went to ($90,000), they flushed it,” Mulcair said on CTV’s Power Play.

“So was it a question of principle or is it a question of price? Because if Gerstein is doing the same thing for which he’s reproaching Wright, he should have been thrown under the bus as well and yet he’s still sitting behind the prime minister in the Conservative caucus.”

Trudeau and Mulcair both asked during question period why Gerstein has not been disciplined after RCMP documents alleged he used a contact at Deloitte to inquire about its independent audit of Duffy’s expenses and whether the work could be stopped if Duffy’s ineligible claims were repaid.

“The RCMP says Irving Gerstein called Deloitte twice to interfere with their audit of Mike Duffy’s expenses,” Trudeau said Wednesday.

“He tried to back channel audit information and then pressed on hoping that Nigel Wright’s $90,000 payment would make that audit go away. So will the prime minister please explain to Canadians why Sen. Gerstein still enjoys his complete confidence?”

“What is at issue is that Mr. Duffy made claims to repay inappropriate expenses when he had in fact not done that,” Harper replied.

“That was actually done by Mr. Wright and obviously that information was not properly disclosed to me or to others. For that reason those two individuals are under investigation and we have taken action against them.”

Trudeau pressed on, asking why Gerstein remains the chair of the Senate banking committee and of the Conservative Fund after he OK’d a deal for that donor fund to repay Duffy’s ineligible expenses when they were thought to total $32,000. RCMP documents indicate Gerstein balked at having donor money pay Duffy’s expenses when the amount ballooned to $90,000.

Harper repeated his claims that all he was told was that Duffy was to repay his own expenses, and it’s the two men who are under investigation.

“Is that the PM’s code of ethics, the criminal code?” Mulcair replied. “In other words, if you’re not under criminal investigation by the RCMP, no matter how reprehensible, it’s not really wrong? Is that the standard that he’s holding his government to? What’s the ethical difference between a $90,000 cheque from Nigel Wright and a $32,000 cheque from the Conservative Party? Ethical difference. A hint: the answer is not $58,000.”

“There are two individuals who are responsible for the inappropriate payment in question, a payment that was made without authority and that was not properly reported or disclosed,” Harper replied. “And in this party we hold those who undertake actions responsible for their own actions.”

Mulcair noted on Power Play that when he is asked about Gerstein, the prime minister “not only stays silent on Sen. Gerstein, he won’t even pronounce the man’s name.

“That’s fascinating, because we’ve asked him a whole bunch of questions about Gerstein and he clams up on it. There is something going on there and we’re going to keep asking questions.”During question period, Mulcair also asked why Sen. Carolyn Stewart Olsen also remains in the Conservative caucus despite a claim Horton that she gave information that was “incomplete and not consistent with the facts” when she was interviewed by investigators.

Again, Harper pointed out that it is Wright and Duffy who are under investigation.

Mulcair also wondered if the prime minister had agreed to abide by talking points that Duffy demanded in exchange for repayment of his expenses. The talking points included a stipulation that the Conservative caucus would publicly say Duffy met the Senate’s residency requirements to serve as a senator from Prince Edward Island.

“The prime minister’s own staff guaranteed in writing that the prime minister himself would publicly state that Mike Duffy met the residency requirements to sit as a senator from PEI,” Mulcair said. “Again, did the prime minister know that his office agreed in writing he’d probably vouch for Mike Duffy as part of their cover-up deal? That’s in fact what he did. Is he going to try to pretend he didn’t know?”

“The RCMP interviewed everybody involved, the RCMP looked at thousands of emails, the RCMP said clearly the prime minister had no knowledge of any such payments to Mr. Duffy,” Harper replied. “They are absolutely clear, the leader of the NDP if he had any honesty, would accept that judgment.”

Harper later responded to a question about an email from Wright saying that Harper was aware that he had personally assisted Duffy with his expenses with the correct quote from the RCMP, which is that the lead investigator is “not aware of any evidence that the prime minister was involved in the repayment or reimbursement of money to Sen. Duffy or his lawyer.”

None of the allegations in the RCMP documents have been tested or proven in court.