A married couple who worked at the South Australian health department sent themselves thousands of death threats in an elaborate ploy that scored them free holidays, a court has heard.
But they were thwarted by police who fought cunning with cunning, breaking into the pair's home to mark paper and envelopes with "invisible ink".
Tabitha Lean and Simon Peisley are each charged with 47 counts of deception and on Wednesday, they faced the opening of their trial in the SA District Court.
They mailed crude letters and bloodstained parcels to their home and office so they could take indefinite time off work and interstate trips at their employer's expense, prosectors allege.
They faked a total of 80,000 threats - comprising letters, parcels and phone calls, and vandalising their own home - over a two-year period, the court heard.
Some of the parcels contained pieces of their children's clothes stained with what looked like blood.
"They even went so far as to send their children items at school," prosecutor Chris Edge said.
"All of this was a clever, sophisticated and very well executed lie.
"They were in this together all of the way. A willing, effective and loyal partnership."
Many of the letters said the couple were not safe at work, or demanded Lean step down from her management position in Aboriginal health services at SA Health.
Because of the link to work, their employer allowed the pair to take indefinite time off with almost full pay, and funded family holidays to Melbourne and the Gold Coast.
The state government also put them up in a North Adelaide apartment so they didn't have to stay at home, while their medical and pharmacy expenses were also paid.
But police began to suspect Lean and Peisley, aged 40 and 37, were behind the threats and devised their own plot to catch them.
Police secretly broke into the couple's apartment and when they found a stack of envelopes and paper, marked them with a special invisible ink.
"They covertly entered the apartment, then snuck away, leaving no trace they had been there," Mr Edge said.
The next threat the couple received, and handed over to police, was tested with a UV light, revealing the invisible markings the officers had made.
The couple were arrested soon after.
DNA samples, handwriting analysis and other evidence will be used in the prosecution's case.
The trial continues.