The association representing professional engineers in Manitoba is investigating allegations a seal belonging to one of its members was copied on to blueprints used to build three Winnipeg houses.

While the City of Winnipeg is conducting its own investigation into the situation, the Association of Professional Engineers and Geoscientists of Manitoba is using the opportunity to introduce a new fraud-busting technology to protect that valuable seal.

The seal "is really our badge of responsibility. We are saying that 'I take responsibility for this drawing or this report that I am producing' — that I've put my personal stamp on," APEGM president Dawn Nedohin-Macek told CBC News on Tuesday.

Professional engineer Les Frovich's seal appears on the blueprints at the centre of a dispute between the city, a design company and a building company.

The city believes a home built by Hollywood Homes on Pritchard Avenue and another on Chevrier Boulevard used blueprints from InterPro Building Design, a company owned by the wife of Winnipeg building inspector Sig Steinhilber.

Dawn Nedohin-Macek, president of the Association of Professional Engineers & Geoscientists of Manitoba, believes a digital seal will prevent fraudulent use on blueprints. (Courtesy of APEGM)

Both companies have denied altering the documents, but that's cold comfort to Frovich.

"I was shocked," Frovich said after discovering his seal on the doctored blueprints. He approved the design, he said, but not for the suspect addresses.

One of the sets of blueprints clearly shows the original address on Manitoba Avenue was scratched out. A Pritchard address was handwritten in its place.

"Professionally it means my stamp is being used without my knowledge or my permission," Frovich told CBC News, adding it leads to liability and insurance considerations.

It's not the first time something like this has happened.

Tony Eshmade, an engineer with nearly 50 years' experience, told CBC News he has suffered the same fate twice: one 20 years ago and again just five years ago.

"An engineering stamp forms a legal document, and it was signed and it was dated but none of it coincided with any records or information we had," Eshmade said of one case.

"We realized it wasn't one of my drawings at all. Somebody had cut my stamp off another drawing and put it on this set of drawings and was passing them off as being stamped by me — which it wasn't."

Stories like that have the APGEM championing a digital seal that notifies users immediately if a document is altered.

"If I sent that to you and you opened it and edited it, immediately that [seal] is broken so anybody else looking at that document would know that it is no longer my sealed document — it doesn't have my signature on it anymore," Nedohin-Macek said.

The city hopes to complete an internal report on its own investigation into the bogus blueprints in two weeks.

With files from Katie Nicholson