Warning: This story and related coverage of the trial contain graphic details that may be distressing for some readers.
More women are expected to come forward to the police now it has been revealed Grace Millane's murderer was a repeat sex offender.
Since being found guilty of killing the British backpacker, Jesse Kempson has also been convicted of raping one woman and assaulting another multiple times.
The two women told the police what Kempson had done to them after they realised he was the man charged with killing Grace Millane.
Following the murder trial last year he went on to face two further trials at the High Court at Auckland.
In both, he was found guilty on all charges, including rape; and the sexual violation; physical, sexual, emotional and financial abuse of an ex-girlfriend.
"I've always thought that if it wasn't Grace, it was going to be someone," Detective Inspector Scott Beard told RNZ's Checkpoint, after Kempson was sentenced in February to life imprisonment with a minimum non-parole period of 17 years for Millane's murder.
"I'm not a psychologist, so I can't talk about psychological profile, but what we do know is he is a liar.
"A number of times we proved he lied. He lied to the police, he lied to others."
Mark Longley, the father of the Emily Longley, who was killed by her former boyfriend in England nine years ago, was said Kempson's predatory behaviour does not surprise him.
"There was a pattern building with this guy, and it often starts out with very low-level abuse, and it just grows and grows and grows, until unfortunately with Grace it ended in her murder.
"I just thought it was sad that other women have had to go through that, but it's not surprising that there's a pattern of behaviour like that."
There's still not a good recognition of what abusive behaviour is, Longley said. He's an ambassador for White Ribbon NZ, the campaign to end violence against women.
Education is key in helping prevent abuse, rape and murder of women, he said, and it's on men to recognise ugly behaviour early on, and call it out.
"I don't know Jesse Kempson, but I suspect there's something similar as there was with Elliot Turner, who killed my daughter, Emily," he said.
"Perhaps if that behaviour had been recognised earlier, they probably wouldn't have gone on to murder.
"And that's why it's so important I think to recognise these signs and act on these signs, because it does lead to murder.
Reform to help victims come forward
While education is the strong fence at the top of the cliff, director of White Ribbon, Rob McCann said there needed to be an accepting justice system at the bottom, so people were more comfortable taking action against their abusers.
"We know it's an absolutely degradating experience for many women to go through that court system," McCann said.
"It needs to change, and it's not because the police aren't trying, it's not because the judicial system isn't trying, but the whole system needs to change, as it understands these offences."
There are also other laws that could be introduced to make it easier for such people to be convicted. He cited the Domestic Abuse Act in Scotland, which creates a single offence covering psychological, financial or sexual abuse.
"Instead of just looking at the one offence that we look at in New Zealand, which would be the end offence, where there's some very serious violence, it can look at a pattern of behaviour.
"In New Zealand, we really do understand what physcial violence is. But we know that psychological abuse can be even more harmful.
"Over there, they're able to look at a pattern of behaviour and bring a charge based on that pattern."
'No blame here' for other women
Detective Inspector Scott Beard - who ran the investigation into Grace Millane's murder - had been in touch with the two women at the centre of the other prosecutions.
"They feel they take a bit of the blame, but there's no blame here," he said. "The person accountable for their actions is Grace's murderer, and he's been held to account."
Debbi Tohill from Rape Prevention Education suspects there are other women who have been targeted by Kempson.
"I would strongly encourage anyone who was considering doing that now, that they contact organisations such as Auckland Sexual Abuse Help, because they can actually provde a person to go with them."
Justice Venning, who convicted the killer on the rape charge cited a cultural report about him saying the fact that his father was at times violent, and his mother rejected him, may go some way towards explaining his attitude towards women.
"That is pretty shocking. We talk about mitigating factors, and I guess that's where the Judge's comments are coming from.
"But at the end of the day, there is absolutely no excuse for raping someone, and murdering someone. No matter what your childhood might have been like."
Kempson is serving a sentence of 17 years without parole for Grace Millane's murder, alongside 11 years for the rape and sexual assaults of the two other women.
RNZ
