In his opening at the start of the trial, defence lawyer Jonathan Krebs called the investigation launched against his client was "extraordinary".
"You're the first jury in the country to hear of such a thing," he said.
Reddy allegedly participated in several "simulated crime scenarios" alongside undercover officers and at the end of the operation he made admissions about the deaths of Ms Yusuf and her daughter.
He told an officer that he had killed them and buried the bodies.
Days later he unwittingly took police to the site under the Takapuna overbridge where the bodies were later found.
Mr Krebs said the confession was a lie, made up under "immense pressure".
"What if a person didn't commit the crime but knew enough about the crime to give a plausible narrative?" he said.
Earlier today, the court heard evidence about cash being withdrawn from Ms Yusuf's account after she was dead, according to the Crown case.
The Crown alleges she and her daughter were killed at the end of 2006 or start of 2007 but after that period, significant cash withdrawals were being made from ATM machines.
Police intelligence analyst Helen Little said there were changes in the patterns of all three parties' bank accounts from December 2006 onwards.
In 2006, Ms Yusuf's account saw about 50 transactions per month - automatic payments, eftpos debits and ATM withdrawals.
Documents placed before the jury showed trips to Burger King, The Warehouse, superettes.
In February and March 2007 - when she was dead, according to the Crown - there were no such eftpos debits, only cash ATM withdrawals.
Unlike the sums Ms Yusuf had previously taken out, they were sometimes upwards of $500.
Ms Little also reviewed Reddy's Kiwibank account over the same period.
In 2006 there appeared to be regular transactions, sometimes numbering more than 40 a month.
By the middle of 2007, at times there were fewer than 10.
Detective David Sanday gave evidence this morning of statements that Reddy had made to police in 2013.
He said Reddy told him he and Ms Yusuf used each other's bank accounts and knew the pin numbers to one another's eftpos cards.
The court also heard how the defendant allegedly told police the last time he had seen his partner was when she was getting a taxi to the airport to meet an aunt who was arriving from Australia.
The defendant believed they had then gone to Hamilton or Wellington.
Reddy claimed everything was "normal" in the relationship at the time.
