An Auckland man is beginning what is believed to be the longest minimum non-parole period given to a child murderer in New Zealand.
Joel Loffley will spend at least 19 years in prison for killing his two-year-old stepson James Lawrence, known as JJ, in November 2011.
The toddler suffered at least 32 injuries in his short life that ended when his Loffley assaulted him so severely that some of his organs, including his liver and pancreas, split.
Loffley was found guilty of his murder last year and appeared for sentencing at the High Court in Auckland on Thursday.
Two of JJ's aunts gave tearful statements to the court, describing Joel Loffley as a monster.
Roxanne Ruhe said she feels only anger and hate towards Loffley, whom she described as an inhumane, sick and twisted individual. Danielle Ruhe said Loffley was a hateful monster and coward for what he did to an innocent, harmless boy.
Statements from JJ's mother and father said how empty their lives were without their son and how they feel to blame for not being able to protect him.
Joel Loffley maintains that he did not kill JJ, but says he wishes he had done more to protect the toddler.
But Justice Keane rejected that on Thursday, saying the assault was brutal, callous and a huge breach of trust.
"To have caused his liver and pancreas to split - which are extreme and rare injuries - you must have used extraordinary force.
"The likelihood is, that when you punched JJ or kicked him, you had him pinned so that he could not move and so that his small body would absorb the full force of your assault."
Crown prosecutor Phil Hamlin asked the court to order that Loffley serve at least 17 years behind bars.
But Justice Keane said the killing and the number of assaults that took place before the toddler's death were so brutal that the minimum non-parole parole period of 17 years usually given to murderers was not enough.
Loffley's family members said they did not know how they felt about his declaration of innocence, but will stand by him if he decides to appeal.
The killers of Rotorua toddler Nia Glassie had the longest minimum jail term previously for a single murder of a child. In 2009, they were sentenced to at least 17-and-a half-years' jail.