Criminals in Africa have tried to sell another two Perth homes without the owners' knowledge - taking the number of attempted property frauds reported to authorities since 2008 to seven.
The latest separate cons involving properties in the northern and southern suburbs were foiled by WA real estate agents but not before the criminals had convinced property management staff at the agencies they were the homes' owners and tricked them into changing contact details and sending them documents.
The major fraud squad is trying to track the criminals, while the Department of Commerce investigates the actions of staff at the agencies.
Such scams first made headlines in September 2010 when criminals sold Wembley Downs retiree Roger Mildenhall's investment property without his permission while he was living in South Africa. Eleven months later, a Ballajura family fell victim to a similar scam while living overseas.
Those crimes led to police fraud squad seminars to teach real estate and settlement agents how to detect and prevent similar scams.
Authorities are unsure if all seven cases are linked but Consumer Protection Commissioner Anne Driscoll said that in six cases the real owners had been living in South Africa and in the seventh they were living in Nigeria.
There is speculation the criminals intercepted mail in Africa, giving them information to launch each scam.
In the latest cases, the owners were living and working in Africa and had their properties leased and managed by WA real estate companies.
Ms Driscoll said the criminals masquerading as the owners had called the agencies "out of the blue" in December wanting to change the contact details for correspondence.
Ms Driscoll said although the frauds were detected fairly quickly she was concerned and disappointed that property management staff had not noticed the warning signs.
She said staff had to confirm any request for contact detail changes through the original contacts and set up a security question with owners to verify they were dealing with the right person.
The agencies involved were not identified but would be if any disciplinary action was launched, Ms Driscoll said.
A Mirrabooka real estate agent is facing action in the State Administrative Tribunal over the fraudulent sale of a Ballajura home last year.