The discovery of an email account previously thought to have been deleted — belonging to former Prime Minister's Office lawyer Benjamin Perrin ​— raises questions about the deletion policy and how the discovery came about.

Perrin was one of the PMO staffers who the RCMP allege knew about a deal between Nigel Wright, Prime Minister Stephen Harper's former chief of staff, and Senator Mike Duffy.

The RCMP allege Wright and Duffy committed bribery, fraud and breach of trust when Wright gave Duffy $90,000 to pay off the senator's questionable expenses. The RCMP allege Duffy agreed not to talk to the media in exchange for keeping his Senate seat and allowing Wright to pay off his expenses.

Benjamin Perrin was one of the PMO staffers who the RCMP allege knew about a deal between Nigel Wright, Prime Minister Stephen Harper's former chief of staff, and Senator Mike Duffy. (Canadian Press)

RCMP Cpl. Greg Horton says Harper ordered the PMO to retain all staff emails in May 2013, in case investigators were to need them. In court documents filed last month, Horton said the RCMP were told Perrin's emails had already been deleted because he left the PMO at the end of March, before Harper gave the instruction.

But a letter released by Harper's spokesman over the weekend revealed that Perrin's email account was still accessible and would be turned over to investigators.

Here are three questions raised by that discovery.

1. Why does the Privy Council Office routinely break the rules by deleting email accounts?

The Privy Council Office is the civil service working for the prime minister, as opposed to the political staff who work for him in the PMO. It is the office that notified the PMO and the RCMP over the weekend that Perrin's emails were still available.

Treasury Board rules, the guidelines under which the public service operates, say records must be preserved unless they are "transitory," or messages that are only needed for a limited amount of time. That doesn't include "records required by government institutions or ministers to ... make decisions, or to account for activities of government," according to the guidelines. Guidelines for departing employees cover deleting transitory records and filing other records "so that the information continues to be accessible to other employees."

Still, the Privy Council Office letter to the RCMP says it is "operating protocol" to "close and delete email accounts of departing employees of the PCO and the PMO as a matter of course."

2. Why didn't the PCO know that the account still existed?

The letter from Isabelle Mondou, assistant secretary to cabinet at the PCO, says her office told the PMO that Perrin's emails had been deleted when he left at the end of March.

Twice in September 2013 the PCO repeated that when the PMO asked about Perrin's emails, Mondou wrote.

It wasn't until the end of November that the PCO discovered the account had been frozen and preserved, she wrote.

New Democrat Leader Tom Mulcair seized on that line in question period Tuesday.

"If Ben Perrin's emails were frozen due to 'unrelated litigation' as the Prime Minister's Office has claimed, wouldn't the head of legal operations have had those emails all along? Who did they ask?" he said.

Liberal Deputy Leader Ralph Goodale followed the same line of questioning.

"Who ordered the retention of Perrin's files? Who had custody of them? Has that person been unconscious for the past six months? And what is being done by the clerk of the Privy Council and the Department of Justice to ensure no more evidence is contaminated?"

Industry Minister James Moore, who answered questions in Harper's absence, pointed to Mondou's letter.

"The Privy Council Office has taken responsibility for the mistake that they made in not handing over the information to the RCMP," he said.

3. What made the RCMP keep asking questions about the emails?

Moore said in question period that the RCMP now have copies of Perrin's emails.

After being told in September that they weren't available, the Mounties went back to the PMO last week to ask whether there were other options.

The investigators contacted the PMO to see whether the emails were available from "any other source," Mondou says in the letter.

"In response to this inquiry on Nov. 29, 2013, we found that Mr. Perrin's emails had in fact been retained due to a litigation hold on an unrelated matter," she wrote.

Canadians will likely have to wait until the next RCMP affidavit is filed in court to see what was in Perrin's emails.