Ms Hoffman-Tamm's body lay on her kitchen floor for more than a day before Sloane wrapped up the body, put it in her car and buried it in a ditch near Murupara.
Justice Keane called the attack brutal and callous and said Sloane's intention could only have been to mutilate Ms Hoffman-Tamm.
Ms Hoffman-Tamm's 25-year-old son Rhys Hoffman read out his victim impact statement in court, pausing several times to compose himself. He told how he was struggling to cope with what had happened to his mother.
"I have lost all trust in the world and I understand when people say they have lost everything and it's gut-wrenching,'' he said. ``I never got to make up for all the times I wasn't there for my mum.''
He said when his mother was missing he never imagined it would turn out like this.
"I was willing to take on anything but now my outlook has changed,'' he said.
Victim impact statements from five other family members had also been presented to the court, all speaking of their added grief at the gruesome manner in which Ms Hoffman-Tamm died.
Outside of court after the sentencing, Mr Hoffman said he had been hoping for a longer sentence.
"There's not much we can do other than take it and move on and hope that everyone else is going to do the same.''
