Jason Somerville was an insignificant, nondescript person dominated by his wife, according to a criminologist.
Greg Newbold said the House of Horrors murderer displayed the same kind of behaviour as serial killers like Son of Sam, who admitted killing six people during a shooting spree in New York in the 1970s.
"He's finally decided to assert his manhood with an act of extreme violence towards women who are the object of his insecurities," said Newbold.
"If it's true about Tisha coming into his house and walking around and him being powerless to stop her doing it, that would have aggravated any feelings of inferiority or insecurity and powerlessness that he had.
"He overcame that by showing her who was boss and killing her. The ultimate domination was having sex with her after he killed her."
Newbold drew up a profile of Somerville after reading excerpts from the transcripts of his interviews with police. He said Somerville's wife Rebecca was the "true source" of the killer's insecurities.
"Refusing to have sex with him, possibly treating him with contempt ... he showed her who was boss as well. And having sex with her was just to finish the whole thing off, the icing on the cake, the coup de grace of his masculinity."
Newbold thought Somerville confessed because he was "pretty messed up" and would have been relieved afterwards.
"He would have been an absolute train-wreck. I think he knew that he was going to get caught and was just waiting for police to come around. He probably knew that once his wife was found it was all over for him."
Somerville may have enjoyed the publicity when his crimes were made public, said Newbold.
"Being an insignificant individual, he may have revelled in the light of the publicity. It's common in these cases. He is not a serial killer but fits the profile.
"Serial killers love the notoriety their crimes give them. It's the first time in their lives that they've done something significant. He may be getting some pleasure from the fame."
He said Somerville's lack of remorse and emotion at sentencing, even when the victim's families read emotional statements to him, was typical.
"He may have been thinking more about the television cameras. You just don't know what's going on in their brains."
Greg Newbold, who likens Jason Somerville to the Son of Sam killer. Photo / Christchurch Star
