OTTAWA - A federal civil servant found a novel way to beat the high cost of gas by filling up on a government credit card and then disguising the charge as a travel claim.

Newly disclosed records show the gas scam continued for at least five years before the fraudster was caught, though no charges were ever laid.

Instead, the worker was allowed to take a paid leave and then retire quietly last year after a promise to repay the money.

The heavily censored documents, obtained by The Canadian Press under the Access to Information Act, shine light on how federal managers deal with workers who systematically steal from taxpayers over many years.

The unidentified employee, a project officer with Public Works and Government Services since 1987 who apparently worked with native bands, was required to travel frequently _ 119 business trips in a rented vehicle between 2001 and 2005.

His manager twigged to high gas costs on the expense claims sometime in 2005, and detailed sleuthing by internal investigators uncovered the scam.

The individual, whose name and other identifying information was carefully blacked out on the documents, would frequently gas up at a Shell station near home using a corporate American Express card.

Investigators assembled a pastiche of credit-card receipts, rental-car records, Interac withdrawal records and expense claims to demonstrate that the gas he pumped was far more than needed for his frequent two- or three-day official trips in rental vehicles.

Typically, the Shell receipts would show suspicious fill-ups of between 43 and 48 litres, though there was no hard proof that the gas went into the worker's own SUV.

Confronted with the evidence on Dec. 15, 2005, the worker "attributed the over purchase of fuel to bad road conditions and to stopping and starting (the) vehicle."

The worker also "emphasized that (he or she) travelled under poor winter conditions and ... considered this to be a major factor in the usage of fuel."

The suspect took at least five months of sick leave soon after the meeting, and retired in October last year.

"The case seems to be heading toward a gas theft of perhaps up to 3k over 4-5 years," says an e-mail by a senior labour relations official at Public Works.

"It seems to me that the case is pretty straightforward and that the amount is not such as to interest the RCMP."

Another note in the file indicates the person was required to pay back $2,600, though it's not clear how the number was calculated. The released documents indicate the department lacked detailed expense records and receipts for most of the years in question.

A spokeswoman for the department declined to discuss the case, citing privacy rules.

"The employee agreed to repay an amount," Lucie Brosseau said in an e-mail response to questions. "We can't release further information in accordance with the Privacy Act."

Brosseau added: "The RCMP was not brought in as the amounts involved were minimal, and there was insufficient evidence to warrant an RCMP investigation."

The department undertakes about 30 such investigations each year, and over the last two years none have led to criminal charges, she said.

The gas-scam case bears similarities to another expense-claim fraud at the department that was spotted by a part-time clerk in 2004.

A Public Works employee who reported to an Edmonton office also abused the system, with forged signatures on expense claims, bounced cheques and personal items charged to the public purse.

That employee was also allowed to retire quietly last year, with no charges laid. The government recouped $5,871 by deducting amounts from retirement benefits.