The charges stemmed from living expenses Harb, a one-time Liberal MP from Ottawa, filed for a secondary home in the city while claiming his primary residence was far from the national capital.

One month after the sensational acquittal of Sen. Mike Duffy, prosecutors made it official Friday that Harb, 62, would not face a criminal trial because the Crown did not see a reasonable prospect of conviction.

OTTAWA — Charges of fraud and breach of trust have been dropped against former senator Mac Harb, a Liberal appointee and central figure in the Senate expense scandal whose housing expenses were deemed unjustifiable by the upper chamber.

Former senator Mac Harb arrives at the East Block of Parliament Hill in Ottawa on May 29, 2013. (Photo: Sean Kilpatrick/CP)

A Senate audit raised doubts about the veracity of his claims and Harb ended up repaying the Senate about $231,000 in housing expenses going back years.

Harb, who retired from the Senate three years ago, had been set to face a criminal trial later this year.

In a statement, Harb's lawyer Sean May said his client has "steadfastly maintained his innocence throughout the arduous process" of the RCMP investigation, one in which he co-operated fully.

"The withdrawal of the charges is a complete vindication of Mr. Harb, legally and ethically," May said.

Last month, the 31 expense-related criminal charges Duffy had been facing were dismissed in sensational fashion by an Ottawa judge, including counts of fraud, breach of trust and bribery.

Duffy, Wallin in the clear

And on Thursday, the RCMP abruptly announced that it wouldn't pursue charges against Sen. Pamela Wallin, closing her file after three years of poring through her travel expenses.

Friday's decision makes it clear that investigators and the Crown have been reconsidering their options since the Duffy verdict.

The decision on Harb's case leaves only one senator still facing a trial: Conservative appointee Patrick Brazeau, who is — for the moment, at least — scheduled to face trial next year on charges of fraud and breach of trust.

Harb entered politics as an Ottawa alderman in 1985. He served as deputy mayor before making the leap to federal politics in 1988 as the member of Parliament for Ottawa Centre. He held that seat through four consecutive federal elections.

In 1994, Harb was appointed parliamentary secretary for international trade. He was named to the Senate in September 2003 by then-prime minister Jean Chretien.

In early 2013, the Senate began taking a closer look at the living expenses of Harb, Duffy and Brazeau amid concerns that all three, who lived in or close to Ottawa, were improperly charging the Senate for housing allowances.

Senate rules allow senators to claim expenses for two homes if their primary residence is more than 100 kilometres from Parliament Hill. Harb claimed his primary residence was in a home just beyond that limit, qualifying for the annual subsidy of about $20,000 for his years in the Senate.

The Senate committee charged with oversight of spending ordered outside auditors from Deloitte to review the trio's spending.

For Harb and Brazeau, the auditors argued the spending rules were unclear, making it difficult to tell if they'd been broken. That same refrain would be echoed by the company that audited the Senate's financial statements and from witnesses at Duffy's criminal trial.

Even before Harb's trial, his lawyer had publicly suggested those findings that the rules were unclear

Harb's audit suggested he didn't spend a lot of time at his primary residence outside the city, even though that wasn't part of the rules, and senators decided that was enough to order him to pay back the money.

An RCMP investigation into Harb's spending made sweeping allegations that Harb's primary residence was allegedly "uninhabitable" for three years, and that he maintained a 0.01 per cent ownership stake in the house after selling the rest to a diplomat from Brunei who subsequently left Canada.

But the Mounties said there wasn't enough evidence to charge Harb with mortgage fraud when they laid the fraud and breach of trust charges in February 2014.

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