Gavin Gosnell has been found guilty of murdering 15 year old Hayden Miles.
Gosnell had already admitted attacking the teenager, before cutting up his body and burying it in different cemeteries in Christchurch in August 2011, but he denied murder, saying he didn't mean to kill him.
But on Tuesday the jury at the High Court in Christchurch found Gosnell guilty of murder.
In a statement, Hayden Miles' father's family said they were pleased with the verdict, but would never come to terms with the extreme violence and cruelty that Hayden suffered at Gavin Gosnell's hands.
They also condemned those who knew what had happened to the teenager but did not come forward at the earliest opportunity.
The family said that through their inaction, those people condoned Gosnell's heinous behaviour.
Hayden Miles' aunt, Sandy Ward, representing his mother's family, said they were extremely relieved the trial was over.
"We would like to thank the jury for their decision as we know this trial would have been emotionally very difficult to hear."
Gosnell will be sentenced on 5 June.