After nine months and more than $160,000, the case of the oil leak found next to the Optometrists Building remains shrouded in mystery.

Bryan Levia, Environment Yukon's monitoring and inspections manager, said last Thursday his and other government agencies that have helped in the investigation Environment Canada, the Department of Fisheries and Oceans and the City of Whitehorse are stumped.

'There's still free product entering the sump beneath the Optometrists Building,' he said in an interview. 'It's less than a litre a week.

'The consensus with all of these people is that it's really strange that we're unable to find the source of this fuel,' Levia said. 'I think we're looking in the neighbourhood of between $160,000 and $170,000 (that we've spent) so far.'

Levia said during the course of the nine-month investigation, he's also had a number of parties outside the government help out with the search, but that investigators were still coming up empty.

'We have used Gartner Lee Ltd., they have engineers and hydrogeologists that have been used. We have brought in a drilling company from Outside. We've brought in a tank testing company to test the tanks of one of our potential suspects.

'We've had North of 60 and Summit Fuels (participate),' he said.

The case of the leaking fuel began last March 28 when an oil sheen was discovered in the Yukon River.

Government investigations tracked down the leak to the Optometrists Building on Second Avenue, but, to date, officials still don't know where the fuel is coming from.

The investigation, spearheaded by Levia, has seen fuel delivery records of dozens of residences and businesses downtown accessed, tanks in the area tested, a series of holes drilled and the testing of fuel.

Fuel tests, Levia said, have proved the oil is less than a year old, originated from North of 60 or Summit Fuels and showed that it had not travelled very far underground.

'Those are the only records that we looked at,' Levia said.

Fuel records for Great Northern Oil were not accessed because it was a different type of fuel, coming from Alaska and not from down south, he said.

While the government currently gets its fuel from North of 60, it was receiving its fuel from Great Northern at the time the fuel was discovered. So, Levia added, YTG is not considered a prime suspect in the oil mystery.

'When they have it analyzed, they do something called gas chromatography. Basically, it gives you a graph of the carbon atoms of the molecules that they're analyzing.

'These graphs become like a fingerprint,' Levia said. The government's fuel fingerprint did not match the fuel fingerprints found under the Optometrists Building, he added.

He could not completely rule out the government as a potential source for the leak, he said.

There are still numerous possibilities of who could be responsible, he added.

'Dozens and dozens; residences, businesses, commercial operations, residential operations, apartment buildings (downtown had fuel delivered by the two companies),' Levia said.

'Through the course of our investigation ... we have had a number of people contact us.

'Every call and every lead we get we chase down, but to date, there's been nothing that has helped us find this source.'

Asked if he thought it's strange that no person or business had reported missing $4,000 worth of fuel, Levia said he did find it odd.

'I would think (someone would notice). That's a presumption, but I would think so,' Levia said.

From here, the investigation will take a brief hiatus during the winter months and will ramp up again in the spring.

'Right now, we're going to continue to treat the sump through the winter or until such time that there's nothing there to treat.

'We're going to continue to work with our consultants ... and continue the investigation in the spring,' he said.

Levia encourages anyone with any information to contact the Yukon spill line at 667-7244 or himself at 667-3436.

'If they know anything about it, let us know they can call me directly, they can call the tip line, which is completely anonymous,' he said.

The Yukon government has a polluter-pays policy, meaning those responsible for the leak will have to foot the bill for the cleanup.