He had admitted strangling his near neighbour Tisha Lowry and his wife Rebecca Somerville and burying their bodies beneath the floor of his house in Christchurch's Wainoni Road -- an address that became known as the House of Horrors.
23 years jail for double murderer
His acts in having sex with both the dead women were described as callous and depraved at his sentencing today in the High Court at Christchurch by Justice Lester Chisholm, the Christchurch Court News website reported.
Because he was charged only with murder, his offending did not allow an open-ended preventive detention sentence to be imposed as well as a life sentence.
But because of the life sentence and the facts of the case, he may never be released from custody by the Parole Board.
Miss Lowry's mother Tanya Lowry said outside the courthouse that it had been a very hard day for the family, and it was the end of the justice system as far as Somerville was concerned.
"We just want to get our lives back as soon as possible."
The uncle of Rebecca Somerville, Peter Clifford Marsh, said the family was pleased with the sentence.
"We ask that he gets the assistance he requires to carry on through life."
Somerville, who has just turned 34, killed the women about 11 months apart. He apparently strangled Miss Lowry when she came to his house and refused to leave, and he killed his wife when she refused sex.
In both cases the strangulation was followed by underwear being forced into their throats, sexual intercourse, and burial beneath the house.
Nine members of both families read out victim impact statements in court, recounting their grief and the effects of the loss of loved family members.
They spoke of love for Miss Lowry, disrupted sleep, lack of concentration, and hate of Somerville.
Jacob Lowry, the younger brother of Tisha, referred to Somerville as scum. "You don't deserve to be on this earth," he said.
Miss Lowry's sister, Leanne Hodder, said: "I hate you with so much of myself that the hate I feel has interfered with the rest of my life."
Mrs Somerville's father, Clayton Chamberlain, who lives in Australia, had a statement read out saying: "I really miss Rebecca and feel lost without her in my life." Mrs Somerville was described as "a troubled lady", but the family said they would miss her company, her singing, and her "beautiful, giggling laugh".
One family member read out a poem Mrs Somerville had written in 2001, entitled "I am not a mistake."
Crown prosecutor Brent Stanaway described the sex as a "depraved and sickening act". Somerville clearly posed a danger to the community, and it was clear there was no remorse or empathy with the victims.
He had changed his story since talking to the police in September, when he was recently interviewed by probation and health assessors.
"He has tried to minimise his involvement, and minimise the unsavoury aspects that are likely to make him very unpopular in prison. He has very little insight into what he has done."
Defence counsel David Ruth said Somerville had a difficult start in life, with brain trauma, a head injury, and suffering sexual abuse during his teenage years. However, none of this had resulted in an identifiable mental disorder.
"Right from his early days there has been a worrying trend of strangulation being part of his response to situations that were not of his liking or stressful to him," Mr Ruth said.
Justice Chisholm said the deaths of 28-year-old Miss Lowry, and 35-year-old Mrs Somerville had been devastating for the families and had caused irreplaceable loss.
He said he found it absolutely incomprehensible that Somerville showed no remorse or empathy for the victims. The sexual aspect of the offending could offer a significant indication of future risk.
The judge allowed a three-year reduction in the sentence for Somerville's guilty pleas.
Somerville remained impassive all through the sentencing, though he sometimes frowned and looked puzzled when technical legal aspects were discussed.
