Cory Jefferies earlier admitted killing her but denied it was intentional.
A jury has found Waikato man Cory Jefferies guilty of the murder of his partner Kim Richmond.
The jury of five men and seven woman in the High Court at Hamilton decided he did have murderous intent when he attacked his partner of 26 years on their way home froma party at the Arohena Hall in South Waikato on July 31, 2016.
There were gasps from the public gallery, full of Richmond's family and friends, as the verdict was read.
Standing in the dock, Jefferies remained relatively composed when the verdict was delivered, briefly closing his eyes and looking up to the roof before keeping a gaze at the floor and at the judge, absorbing the impact of what he had just been told.
Supporters of Jefferies were not in court for today's verdict with fewer turning up to court as the trial, which began with the jury hearing evidence on Tuesday, progressed.
Crown prosecutor Ross Douch explained that intent stretched across the spectrum from a well thought out execution to an almost instantaneous killing where the offender knows death is likely but carries on with the act anyway.
A jury has found Cory Jefferies murdered his partner Kim Richmond, above.
"What you're looking at there is that you have a position where the killer reaches a state where the level of animosity or anger to the victim reaches the point where he wants to do them harm and acts upon it but in doing that he realises that level of harm can be fatal and does it anyway."
He also urged the jury to put aside any thoughts that what happened between Richmond and her neighbour was an affair.
Jefferies had always admitted killing Richmond but said it was unintentional.
Defence counsel Tom Sutcliffe said his actions in disposing of her body in Lake Arapuni were that of a desperate man.
However, the post-mortem examination had not revealed any broken bones which he submitted show how little intent there was in trying to kill her.
"The evidence clearly shows that Kim's death … was a spontaneous, unscripted event. How else could it be explained?"
The jury spent six hours deliberating on Friday. They were sent out just after 10am today before returning with their verdict at 10.30am.
Waikato Police Area investigations manager Ross Patterson said it welcomed the verdict.
"Our thoughts are with Kim's family at this time and we are grateful for their support and co-operation through the investigation," Patterson said.
"I would like to thank the investigations team who worked diligently and tirelessly on this case to find Kim, bring her home and seek justice on behalf of her family."
