Hugh Segal, a former top Conservative member of the Senate, says it should formally apologize to the senators who were subjected to legal scrutiny over their expenses.

"The institution has made a mistake — it should admit it made a mistake — and then we can move on with a clear conscience, and Canadians, I think, will feel more strongly, and more positively, about the institution if they do," Segal said in an interview with CBC Radio's The House.

Segal said that members of the Senate's internal economy committee, in recommending the RCMP investigate their colleagues, dragged Senators Mike Duffy, Patrick Brazeau and Pamela Wallin through the mud, suspended them without due process and deprived them of their salaries, treatment that needs to be rectified to put the scandal to rest once and for all.

"Huge reputational damage was done ... there was an attempt at suicide, I mean we're dealing with huge harm to people," Segal told host Chris Hall. "Rather than fix [spending] rules when the anomalies became apparent, the board of internal economy ... decided it was easier to throw them under the bus."

Former Conservative Senator Hugh Segal says the Senate's internal economy committee has done "huge" reputational damage to Senators Duffy, Wallin and Brazeau. (CBC)

Segal added that the Senate should cover all the legal expenses the three senators have incurred as a result of the criminal proceedings and that there should also be a motion to reinstate the salaries withheld during the suspensions.

Their pay and most benefits were cut off for nearly two years, but restored when former prime minister Stephen Harper dissolved Parliament to call the election last summer. Duffy alone was deprived of $155,867.56 in salary during that time.

This now puts them kind of into the ranks of the perpetrators of the Spanish Inquisition - Former Conservative Senator Hugh Segal

Segal, who was the only Conservative senator to vote against the initial suspensions in November 2013, said the RCMP also has some tough questions to answer given their complete "failure" in these cases.

"Police officers do not, in this country, get led off by one group of politicians — the board of internal economy — to destroy the reputation of other politicians. That's what happens in banana republics, or North Korea, or Eastern European old totalitarian states, it's not what happens in Canada. Police have to have objective evidence of criminality," he said.

Former Senator Hugh Segal says RCMP handling of Senators raises questions. 1:05

Wallin's expenses were the subject of a "thorough investigation," after which RCMP decided they would not press charges.

Duffy was charged with 31 offences relating to his expenses. He went to trial and was cleared of all charges in April.

And this week, the Crown dropped its case against Brazeau for two charges relating to his living expenses.

'That's an embarrassment'

And yet rather than turn the page on the whole Duffy affair, the Senate's internal economy committee, under direction from a three-member steering committee, is actually doubling down on collecting funds it says the P.E.I. senator still owes.

The committee and the Senate finance department are after Duffy for some $17,000 in expenses, relating to photographs, makeup and the hiring of a personal trainer — spending that came to light during the trial — even though Justice Charles Vaillancourt cleared Duffy of any criminality relating to these expenses in his April ruling.

The move to collect the money also comes after two of the top-ranking senators on the steering committee told CBC News in April that the "matter is closed."

In a letter sent to the committee on Thursday, Duffy lawyer Donald Bayne said his client would not repay a penny, calling the latest effort to collect funds an "improper collateral attack on the final judgment and factual findings."

"(Vaillancourt's) ruling is a final legal and factual interpretation that cannot be collaterally attacked by the steering committee," Bayne wrote to committee clerk Nicole Proulx.

Segal, who stepped away from the Red Chamber in 2014, said the committee's move is tantamount to torture.

"The notion that the [internal economy committee], not having done enough damage, would try to do this now puts them kind of into the ranks of the perpetrators of the Spanish inquisition and that's an embarrassment to the institution."

He said that moving forward these decisions should be taken out of the hands of senators, and vested with an external auditor so that "senators do not sit in judgment of their fellow senators' expenses."

Marjory LeBreton, the former Conservative leader in the Senate during the expenses scandal, told CBC News in May that she had no regrets about suspending Duffy and that any move to collect back pay should be shot down.

"When you look at the motion we passed [to suspend Duffy], we weren't adjudicating on criminality. We were using rules within the Senate — legitimate rules — to discipline," LeBreton said in May.

"We're not going to go back now and undo an action in the last Parliament that was taken for good and valid reasons," she said.