Key Points:

A judge sentencing the man who killed Tokoroa teacher Lois Dear has found there was a sexual element to the murder.

Whetu Te Hiko was sentenced to life in prison with a minimum non-parole period of 18 years today.

He killed Ms Dear, 66, in her Strathmore School classroom on July 16.

The Crown argued there was a sexual element to the killing, but this was disputed by the defence, which said that could not be proved beyond reasonable doubt by the forensic evidence.

The High Court at Hamilton heard how Te Hiko bashed and suffocated Ms Dear, a new entrants' teacher, as she prepared for the first day of term the next day.

Ms Dear's trousers had been removed and her underwear lowered when her body was found. Her top had also been lifted to expose her bra.

Justice Lester Chisholm dismissed Te Hiko's claims that her clothing had come off in the course of the struggle.

"I'm satisfied there was a sexual dimension. I don't think it existed initially but I'm sure that it did develop during the course of the attack in the schoolroom."

Family in court

Ms Dear's family were sitting in the public gallery and one gave a quiet clap when the judge made his ruling.

Her son Kevin McNeil, daughter Jan Armstrong, and brother Harley Dear were allowed to read victim impact statements to the court.

Earlier, Mr McNeil had been told by police his statement might not be allowed by the court because of statements directed at Te Hiko and the justice system, but Mr McNeil was allowed to read it unchanged.

Te Hiko covered his ears with his hands as Mr McNeil told him he was "pathetic, gutless and dumb".

"I know that our family life will never be the same because of the completely senseless act of undue violence that you committed on my Mum," Mr McNeil said.

He said the thought of his mother's last few traumatic moments would never leave his mind.

"We will never know why," said the 42-year-old.

"Like you," he told Te Hiko, "we have young children. They now have no grandmother."

Ms Dear's niece, Theresa Moore, also read a statement on behalf of Ms Dear's 95-year-old father, Harley.

Mr Dear snr's statement said of Te Hiko: "I hope they skin him alive. A life for a life."

Justice Chisholm said Ms Dear was much loved by her family, school, friends and the wider Tokoroa community.

"It's patently obvious that she was a kind and wonderful person who would not have harmed anyone."

Te Hiko would have heard the impact of his crime when Ms Dear's family read out their statements.

"It's little wonder that there has been unbridled anger at this cowardly and evil killing," the judge said.

Te Hiko had blamed alcohol for his actions, but the judge dismissed his excuse.

"All too often alcohol and drugs are blamed for violent offending. They offer no excuse and I can tell you Mr Te Hiko, they will not avail you of one iota of this sentence."

The ferocity of the attack had been evident by the photographs of the crime scene, the judge said.

Ms Dear died of asphyxia and a pathologist's report found she was subjected to blunt force trauma to the head and chest. Her injuries included a broken nose and ribs.

The judge suppressed some of the information relating to the state in which her body was found, ruling it was not in the public interest.

He was satisfied beyond reasonable doubt that there was a sexual element to the crime after studying the photos, pathologist's report and forensic evidence.

In the two years before the murder, Te Hiko wracked up eight convictions for violence against women and children.

He had convictions for male assaults female, assault of a child, and threatening to kill which stemmed out of four incidents, the first in June 2004

The judge said Te Hiko clearly had "an unhappy past" but this was not excuse.

"Overall, I doubt that you've got very much insight into this killing, even at this stage," the judge said to Te Hiko.

Te Hiko's appearance had changed from earlier times in the dock.

His head was shaved, exposing scars on his head, which he touched as he sat with his head bowed low and resting in his hands as the Dear family read their victim impact statements.

He appeared angry when his lawyer, Harry Edward, told the judge Te Hiko was not a sophisticated writer but had handed him a letter expressing remorse and asked him to convey the details to the court.

Mr Edward read part of the letter, which said: "My remorse for what I've done is complete in thousands."

Mr Edward paraphrased the rest, saying Te Hiko still failed to understand how he caused the death of "an innocent teacher".

Te Hiko continued to stare angrily at Mr Edward when the judge asked him to stand for sentence to be passed.

Mr Edward and Crown prosecutor Fletcher Pilditch had both agreed the sentence should be life.

When Te Hiko stood, he put his hands in his pockets and appeared almost to smirk, but sighed after the judge said: "I now sentence you to life imprisonment."

The judge said aggravating features of the murder included the "extreme brutality, callousness and depravity of the attack", and the fact there was a sexual dimension and the victim was "an elderly and vulnerable female".

The fact the murder took place in a school room, which was meant to be a safe place, and that the impact of the crime had gone beyond Ms Dear's family, affecting the school and wider community, were also aggravating features.

Te Hiko's record of violence, particularly against women, also counted against him.

Mitigating features in his favour were that he pleaded guilty at the earliest opportunity and cooperated with police.

Without those mitigating features, the judge said he would have imposed a sentence of 20 to 21 years, but he said a discount of between two to three years was appropriate for Te Hiko's guilty plea.