By James Lynn
BBC News, Newcastle
John and Anne Darwin were a couple who liked to "keep up appearances".
On the face of it they were well-to-do landlords who rented out a number of properties across the North East.
They used the extra money to supplement their modest incomes as a prison officer and doctor's receptionist, and owned an expensive Range Rover.
But they were struggling to pay their debts, and with letters from the bank growing more serious, their facade was beginning to slip.
In the months before John Darwin's infamous re-appearance, Cleveland Police received an anonymous tip-off about his "widow's" behaviour.
Her jet-setting lifestyle, including foreign holidays and overseas investment, were described to detectives as out of character.
A covert financial probe was launched, but before the inquiry made much headway John Darwin walked into a London police station.
His story of "memory loss" quickly unravelled and police soon had enough evidence to launch a full, open investigation.
They seized a computer owned by the couple and on it discovered a spreadsheet - last updated just weeks before John Darwin's "death" - which gave some indication of their financial difficulties.
The Darwins were photographed with their Panamanian property advisor
In addition to mortgage and car repayments amounting to about £5,000 per month, the Darwins had more than £60,000 in credit card debt.
But it was an obstacle they could have overcome honestly, according to Det Insp Andy Greenwood, who led the investigation
"Anne and John Darwin owned and rented out 12 properties in the North East, mostly in County Durham, each valued at between £20,000 to £30,000," he said.
"Despite their rental income, it was reaching the point where they couldn't survive on what they were earning.
"But instead of selling some of the houses to pay off their debt, as most hard-working people would have done, they came up with this scam."
Several years later, the Darwins' financial situation was much improved.
After fraudulently claiming £250,000 in life insurance and pension policies, Anne Darwin managed to keep hold of the houses and subsequently made a healthy profit during the property boom.
The couple owned an apartment and land in Panama
By the time she moved to Panama, where her husband was living under the assumed identity of "John Jones", they had amassed about £500,000 in cash and assets, including an apartment and land in the country.
All of which Cleveland Police hope to seize as the proceeds of crime.
Det Insp Greenwood describes the Darwins as "arrogant people who have been liberal with the truth".
"Anne especially was someone who liked to portray a well-to-do image," he said.
"They had built up quite a large property portfolio and it was really beyond them to let it all go.
"They worked together. Anne Darwin would draft the paperwork and then John Darwin would check through it before she signed.
"It was a team operation, and the face of that team was Anne Darwin. But John had all the ideas, including the decision to fake his own death.
"It might seem like a victimless crime, but in relation to the couple's sons - who thought their father was dead - it's a tragedy."