A Canadian naval intelligence officer who has pleaded guilty to spying was selling secrets to the Russian military for about $3,000 a month.

Sub-Lieutenant Jeffrey Paul Delisle, the first Canadian spy to come to light in decades, wasn't lured into a life of deceit, a Nova Scotia court heard this spring.

He volunteered his services to Moscow, walking into the Russian Embassy in Ottawa in 2007 and offering to betray his country for cash.

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The "day I flipped sides," as SLt. Delisle described it to his Canadian police interrogators, came as his marriage of nearly a decade was unravelling.

The naval officer told authorities he didn't do it for money but rather for "ideological reasons" – and was acutely aware his life as he knew it was now over.

"That was the end of my days as Jeff Delisle," the sailor told authorities, according to Crown prosecutors. "It was professional suicide."

A judge in March 2012 placed a publication ban on details of the Crown's case against SLt. Delisle. He entered guilty pleas to one count of breach of trust and two counts of "communicating to a foreign entity" under the Security of Information Act in a Nova Scotia court room Wednesday. As a result of the guilty plea the ban is no longer in effect, allowing details of the government's allegations against the 41-year-old father of four to be reported.

For nearly five years, the sailor stole highly classified and secret information from a treasure trove of material at his work and shipped it to the Russians, a court heard this spring.

SLt. Delisle, who was arrested in January 2012, smuggled out information from top-secret Canadian military facilities using a memory stick hidden in his pocket.

He had access to databases with protected information from Canada and the country's allies through intelligence-sharing systems such as the "Five Eyes" network linking Australia, Canada, New Zealand, the United Kingdom, and the United States.

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The sailor, who had had top-secret clearance for military intelligence since 1998, would hand over the fruit of his espionage about once a month, the Crown said in court.

He would search military computers for any references to the term Russia for the last 30 days and then copy it onto his memory stick.

The Canadian sailor was paid by wire transfer for the first four years of his labour. At first he was paid $5,000 but this quickly dropped to about $2,800 a month and then finally $3,000 every 30 days. This continued until about five months before he was caught, when the Russians changed how they paid him.

The Russians had devised a simple method for SLt. Delisle to hand over information while reducing the possibility the SLt. Delisle's spying dealt a huge blow to Canada, the Crown said, citing intelligence sources. It amounted to a "severe and irreparable damage to Canadian interests," the court heard.

It eroded relations with Canada's allies and reduced the chances that these other nations would share vital information with Ottawa. His superiors at Trinity, the top-secret naval intelligence facility in Halifax opined that the espionage could push Canada's relations with allied intelligence organizations "back to the Stone Age."

The information was mostly military but also contained reports on organized crime, on political players, on senior defence officials. It included emails, phone numbers and contact list for members of the intelligence community.

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The Canadian sailor and his Russian handlers planned for the possibility he might get into trouble, the court heard.

SLt. Delisle also felt pressured to comply with the Russians, who made none-too-subtle threats.

"They had photos of me. They had photos of my children. I knew exactly what it was for," the Crown said SLt. Delisle told them.

The Canadian spy's relationship with Moscow began to change in late summer of 2011. It started with a trip to Brazil to meet his Russian handler, named "Victor."

After repeated requests from the Russians, SLt. Delisle travelled to Rio de Janeiro in the fall of 2011 to meet Victor.

The narrative as retold by the Crown has gaps in it but it appeared that either the sailor or the Russians believed his ability to gather intelligence might be curtailed.

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Moscow proposed that the Canadian Forces member's role change, the court heard. That he become what they called "the pigeon" – the liaison between all agents in Canada working for the GRU. That's the Glavnoye Razvedyvatel'noye Upravleniye, the foreign military intelligence arm of the Russian Defence Department.

The plan was eventually for SLt. Delisle to travel to Austria for more training by Moscow. He never made the trip, presumably because he was arrested in January 2012.

Things began to fall apart on the Canadian sailor's return trip from Brazil. He was pulled aside at the airport by Canadian border officials. They found thousand of dollars in cash on him as well as thousands more in pre-paid credit cards – his new form of reimbursement by Russia.

The interception apparently worried the Russians. The Crown alleged that Moscow wanted the Canadian sailor to lie low for awhile.

By December 2011 however – a month before he was caught – SLt. Delisle was shipping the Russians stolen secrets again.

A message intercepted by Canadian authorities recounted Moscow's delight. "The publishing house is glad to hear your creative juices are flowing again," the Crown alleged that the Russians told SLt. Delisle. "Please send us your manuscript."

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SLt. Delisle pleaded guilty after being charged in January 2012 with passing state secrets to a foreign country. The sailor, who last worked at Trinity, a Halifax naval intelligence hub, faces the possibility of life in prison.