Closing arguments began at the Christchurch High Court on Monday in the second trial of David Hawken and Rebecca Wright-Meldrum in front of Justice Rachel Cunningham, for the murder of the Christchurch woman on 17 August, 1995.
Jeremy Powell confessed to Blackmoore's murder in 2019 and previously appeared as a Crown witness, when he told the court Hawken offered him and Wright-Meldrum $10,000 for Blackmoore's murder.
Blackmoore was bludgeoned and stabbed 39 times in her Wainoni home while her two-year-old son slept in a nearby room.
Hawken and Wright-Meldrum have pleaded not guilty to charges of murdering Blackmoore.
The first trial was abandoned in May after after new material came to hand that lawyers needed time to review.
The Crown argues that Hawken arranged for Powell and Wright-Meldrum to murder Blackmoore with the promise of $10,000.
The defence meanwhile argues that the pair had no motive for the killing.
The jury previously heard from Powell who said Hawken also threatened to kill his family if he did not murder Blackmoore, and he took the warning seriously.
Prosecutor Pip Currie told the jury Powell was a young man who was "well out of his depth".
"Maybe the 49-year-old Jeremy Powell that we see in the witness box would've handled things differently if this had happened.
"But you have to look back and remember this was a young man."
Currie later dismissed arguments made by the defence, around Powell's interest in the Dungeons and Dragons board game.
"Supposedly, because Jeremy Powell played Dungeons and Dragons - the board game with dice and other participants - that translates into him being a sadistic killer.
"I suggest that is totally far-fetched and ludicrous to make a submission like that.
"There is no evidential foundation."
The Crown cited several factors during closing submissions, including evidence by Blackmoore's ex-husband William Blackmoore who claimed Hawken threatened to name him as the instigator of her death.
"The evidence is overwhelming ... absolutely overwhelming and points you (the jury) in only one direction."
The defence began its closing arguments on Monday afternoon.