RCMP's Mike Duffy investigation praised in memo from senior Mountie

Just a few hours before a judge acquitted Senator Mike Duffy of all criminal charges related to his Senate expenses last week,RCMP Assistant Commissioner Gilles Michaud thanked investigatorsfor a job well done.

"As always, we will respect the decision of the court. Regardless of the outcome, I want to take the opportunity to thank those of you who have worked on this very significant file. It is one that generated high public interest and scrutiny. The case is reflective of the types of investigations that we are responsible for here, at National Division," Michaud wrote in an internal message for staff obtained by CBC News.

"I am proud of the tireless work you have done and the professionalism you have demonstrated throughout. I encourage you to maintain this high level of performance."

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• Read Jusice Vaillancourt's ruling

Yet in the end, Justice Charles Vaillancourt acquitted Duffy on all charges and blamed ruthless political operatives within the office of former prime minister Stephen Harper for the entire affair.

For instance, Vaillancourt questioned how it was possible to charge only Duffy with bribery after he accepted a $90,000 cheque from Harper's former chief of staff, Nigel Wright.

"In fact, the RCMP commissioner publicly has stated that there was no evidence of criminal wrongdoing by Mr. Wright, that the facts uncovered by investigators simply did not lead to the conclusion of criminal wrongdoing," Vaillancourt wrote in his judgment.

On July 14, 2014, Michaud held a news conference to announce the Mounties had laid 31 charges against Duffy in relation to allegedly false expense claims, bribery and fraud.

"This investigation started as a referral into expense claims. Since then, investigators followed numerous leads and today's charges are the result of a careful examination of the facts," Michaud said at the time.

Last week, when asked for Michaud's thoughts on the Duffy ruling, a spokesperson responded that "the RCMP respects the decision of the court. It would be inappropriate to comment further."