Ottawa has recovered more e-mail traffic that stands to shine a greater light on the role of the Prime Minister's Office and its top legal adviser in negotiations over the living expenses of Senator Mike Duffy.

The federal government initially believed it had erased all of the e-mails belonging to lawyer Benjamin Perrin when he left the PMO last March. When the RCMP came looking for the communications as part of its investigation into a $90,000 payment to Mr. Duffy from former PMO chief of staff Nigel Wright, it was told that the e-mails had been lost.

However, the PMO announced Sunday night that Mr. Perrin's newly recovered e-mails would be provided to the RCMP "immediately." While it is common practice in Ottawa to delete e-mails of departing PMO employees, Mr. Perrin's e-mails had been protected because of ongoing litigation in an unrelated matter.

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Mr. Perrin was involved in the discussions with Mr. Wright and other senior PMO officials over Mr. Duffy's expense claims that were the subject of an audit earlier this year. Initially, the Conservative Party was expected to repay the claims on Mr. Duffy's part from its own funds, but when the price tag nearly tripled, Mr. Wright decided to pick up the tab himself.

Some of the communications involving Mr. Perrin were already in the hands of the Mounties, as the RCMP already obtained e-mails from other officials involved in discussions with him. For example, Mr. Wright wrote to Mr. Perrin and other government officials on Feb. 22 to state that he would talk to Prime Minister Stephen Harper about a five-point deal to settle the matter involving Mr. Duffy.

"I do want to speak to the PM before everything is considered," Mr. Wright wrote to Mr. Perrin and other staffers.

An hour later, Mr. Wright messaged back: "We are good to go from the PM once Ben [Perrin] has confirmation from [Mr. Duffy's lawyer]."

The Privy Council Office, which is the bureaucratic arm of the PMO, informed the RCMP of its discovery in a letter dated Dec. 1. The documents stand to provide greater context on the discussions, including any legal advice that would have been offered by Mr. Perrin.

"We regret that we previously failed, even if inadvertently, to accurately inform you and the PMO about the availability of Mr. Perrin's e-mails. We apologize for any inconvenience it may have caused," PCO official Isabelle Mondou wrote to the RCMP.

PMO director of communications Jason MacDonald said in a statement that "the RCMP has been very clear that the PMO, at the direction of the Prime Minister, has actively assisted them in their investigation."

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Mr. Duffy and Mr. Wright are the subject of an investigation into allegations of bribery, breach of trust and fraud, according to the RCMP.