Omaha Vaivela, 38, pleaded guilty in Brisbane District Court on Thursday to one count of unlawfully inflicting grievous bodily harm on a 17-year-old boy by kicking and punching him.
Vaivela also aided and encouraged four other juveniles to assault the boy with weapons including a metal pole, guitar and an extension cord wrapped around the knuckles.
The boy suffered facial swelling and abrasions, and a broken jaw that required surgery and insertion of four metal plates to reset.
The group assault took place at 5.15pm on September 24, 2021 in the garage of Vaivela's home in the southern Brisbane suburb of Sunnybank Hills.
Crown prosecutor Katrina Overell said Vaivela heard allegations earlier in the day that the 17-year-old had engaged in sexual activity with a much younger girl.
The four other youths had planned to assault the boy but Vaivela told them not to touch the boy until he had spoken to him first.
"(Vaivela) told him he had to 'take it like a man' and everything that was going to happen 'would stay here'," Ms Overell said.
The court was shown a video of the assault, filmed by one of the youths, that showed the boy seated in the garage while being surrounded by Vaivela and the group.
The video showed Vaivela telling the boy that they are going to deal with the issue right then and he was to tell nobody.
The youths then attack the boy before Vaivela joins in and the boy was punched, kicked and hit with weapons over the course of 10 seconds while lying on the ground and bleeding from the mouth.
After one of the youths calls on the group to stop, Vaivela continued to kick the motionless boy.
For the next few minutes neither the youths nor Vaivela offered the boy aid but were heard to yell insults.
The 17-year-old was later taken to hospital and faced juvenile criminal proceedings for the alleged sexual offending.
Ms Overell said Vaivela had engaged in a clear case of vigilantism and his conduct was not excused by the allegations against the boy he had heard.
Vaivela's barrister John Jacob said the case involved unusual circumstances, and his client's offending was out of character for a successful businessman who made significant donations to the community.
"He did not initiate the violence but he did engage ... he was consumed by anger," Mr Jacob said.
Judge Brad Farr did not accept Mr Jacob's submission that Vaivela's offending was not premeditated.
In sentencing, Judge Farr said Vaivela had engaged in serious offending but was also remorseful and had his emotions running high at the time.
"Vigilantism has long been recognised by the courts as an activity that the courts must not condone," Judge Farr said.
Vaivela was sentenced to three-and-a-half years' imprisonment to be suspended after eight months, with $5000 compensation to the bashing victim.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
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