A woman already convicted of being one of Perth’s most prolific doctor shoppers — who used stolen identities to obtain massive amounts of prescription pain-killers to turn into “homebaked heroin” — has now also admitted a fraud that netted her a $66,000 high-end Holden Commodore.

Brenda Lee-anne Dawson, 43, along with her partner Martin Trubka, was back in the WA District Court yesterday to add to her growing list of dishonesty convictions, this time for a scam in which she used a friend’s falsified work reference and pay slips to convince a Rockingham car yard she could afford the new black Holden Commodore SS-V Redline.

In fact, she had never worked at the company — and Judge Ronald Birmingham said after taking possession of the car in 2014, she used it to “alternately drive between doctors’ surgeries to get the MS Contin to sell”.

That fraud, he noted, was committed just a month after Dawson was placed on a suspended prison order for false representations to obtain a prohibited drug.

Judge Birmingham had previously described the 2014 decision not to jail Dawson immediately as “staggering”.

Yesterday, in hearing more sentencing submissions, he said it was not a course he would be taking again.

“It’s hard to say that you’re on a suspended jail term and you’ve slowly gone back to an offending behaviour six weeks later,” Judge Birmingham said.

The court had previously been told Dawson was a “desperate heroin addict”, who had osteoarthritis.

Camera Icon Brenda Dawson and Martin Trubka Credit: supplied

It was that condition that prosecutor Darryl Carlson said Dawson used to convince medical professionals all over the city the only thing that relieved her pain was MS Contin.

From 2005 to 2011, Dawson attended 741 medical appointments under six identities, which resulted in 710 prescriptions and 35,754 of the pills being prescribed, at a cost to authorities of almost $100,000.

A month later, police launched Operation Beta, which identified Dawson was still obtaining pills for making homebaked heroin.

That was Trubka’s role, until he ended up in hospital with burns.

Desperate for a fix, he tried to explain to Dawson over the phone how to make the heroin herself.

But police were intercepting those calls and others. The pair will be sentenced this month.