The fact none of them pleaded guilty was ''indicative of the people they are. They were never going to own up, they were never going to take responsibility.''
She, along with other friends and family, had been in court for much of the ''extremely tough'' nine-week trial.
''We were here to see justice for our brother,'' she said.
She was ''over the moon'' at the verdicts, which were ''a big step'' in the healing process.
On what the friends and family had gone through since Mr McFarlane was killed, she said, ''You can't even put it into words''.
She thanked prosecutors and police for the ''phenomenal job'' they had done bringing those involved to justice.
''It's a victory for them too.''
Detective Senior Sergeant John Ferguson, who oversaw the case and sat through the trial, said the guilty verdicts were pleasing for Mr McFarlane's friends and family.
''The outcome hopefully will be a step towards a sense of closure for Justin's family,'' Mr Ferguson said.
Because of its complex nature, the case required a significant amount of investigation work by police, he said.
''I'd like to pay tribute to our police staff who have put in long hours and lots of hard work to ensure that the investigation was thorough and of a high quality.''
The verdicts
Guilty of murdering Justin Conrad McFarlane (35) in his Pine Hill Rd farmhouse in Elderslie, North Otago, in September last year, are:
• Robert James Cummings, 23, of Oamaru.
• Steven Kenneth Boskell, 20, of Palmerston.
• Ryan Geary-Smart, 24, of Oamaru.
• His brother, Jacob Christopher Geary-Smart, 23, of Oamaru.
Guilty of being an accessory after the fact of murder is:
• Stephanie Rose McCormack, 27, of Timaru.