As the statements began arriving again, unable to be intercepted, it was Mrs Deakin who found the damning details, proving she was not starting to "lose it" as Coull had claimed.
While the discovery had shattered the bed-ridden Mrs Deakin, a widow since husband Ned died in 2008, Rachel Deakin said her new caregiver had observed that "she's as sharp as a tack".
Coull had done "a fantastic job covering it up". Family had been unable to get to yesterday's sentencing but there had been no signs of remorse from the thief. "She's tried to throw it all back on Valerie," Rachel Deakin said, revealing that a letter had been received threatening action over employment issues.
In court, assigned defence counsel Allan Cressey, of the Public Defence Service, also mentioned the possible employment dispute, but conceded that even if established such a claim wouldn't "come close" to the amount of reparation.
And Rachel Deakin said later that in addition to being paid for her work, Coull's board was covered as part of the caregiving arrangement.
A police summary said that after becoming less mobile early last year, Mrs Deakin entrusted Coull with her bank card and PIN, to make withdrawals for groceries and other items for the household, and other withdrawals amounting to $50 every seven to 10 days.
But in June 2011, Coull began making unauthorised withdrawals of between $50 and $800 a time, averaging about two a week for almost a year.
Coull admitted the thefts when questioned by police, claiming all the money had been spent.
The court was told Coull had almost no resources to pay reparation, apart from promising to pay at the rate set by Judge Tony Adeane, who ordered an immediate means assessment of the thief to establish if she could pay more quickly.
Coull will also be on probationary supervision for nine months.