The Crown states Whatuira had gone to confront Hartley about selling poor quality drugs but instead began loading property into his car.
Wilkinson-Smith said Hartley and Rei had been staying in Hawke's Bay but drove back to Woodville after being alerted to the incident. In the meantime, Troy and Scott Simmonds picked up Fiti and went to the property armed with at least one shotgun, she said.
Hartley arranged for more people to go to his property and when he arrived home he was confronted by Whatuira over the bad drugs, she said.
After lengthy discussions between Rei, Hartley, Whatuira and his associate, Wilkinson-Smith said Rei took a shotgun and blasted Whatuira in the chest.
Whatuira's associate was allegedly told by Fiti not to worry and that it was all over now. She said the associate then left the property and collapsed on the driveway.
Police were called about 3pm but found no one at the house, apart from the body of Whatuira.
Mr Stevenson said his client did not deny killing Whatuira, but says it was self-defence.
He claimed Whatuira had a pistol and refused to leave despite being asked to do so. He says Whatuira went for his pistol, leaving Rei with no choice but to defend himself.
Defence lawyer Peter Coles, who is acting on behalf of Hartley, said his client had no intention of partaking in a confrontation involving firearms. He said Whatuira and his associates were fuelled by drugs and alcohol and were committing an aggravated robbery.
He said Hartley arrived at the property, sat at a table and remained there until after the shot was fired.
Troy Simmonds' lawyer Mike Antunovic said his client had gone to the home to support a friend, not an armed confrontation. He claims Troy did not take any weapons with him and instead found two guns in Whatuira's car, which he took inside intending they be hidden.
Paul Murray, who is representing Troy's nephew Scott, said his client was outside when the fatal shot was fired. He said Scott had no intention of being part of any unlawful activity and did not come into contact with any firearms while at the address.
Fiti's lawyer Simon Hewson said his client was a Black Power member and his role was to extract the fellow member who had accompanied Whatuira.
"That is exactly what he did."
Mr Hewson said Fiti could not have foreseen the events and spent his time sitting on the porch.
The trial before Justice Joe Williams is expected to last up to five weeks.