The jury also found George Ivor Hyde guilty of accessory after the fact to manslaughter between April 16 and 27, 2020.
Mr Watene’s body was found buried in a shallow grave in the Longwood Forest near Otautau on May 18, 2020 and was excavated two days later.
The jury took two days to come to its decision after retiring at 4pm on Tuesday.
The Crown’s case was that Graham had knowingly shot Mr Watene on the night of April 16.
At the start of the trial on June 13, defence lawyer for Graham (32) Sarah Saunderson-Warner said Mr Watene had been shot at Graham’s home but it was not done on purpose nor with murderous intent – it was an accident.
Through defence lawyer Fiona Guy Kidd QC, Hyde also admitted he disposed of the body, but says he was told by Graham at the time, that Mr Watene had taken his own life and he believed her.
The Crown's case was that Graham had intentionally shot Mr Watene on the night he died.
Her defence was that his death was accidental, there had been a struggle with the gun and when the firearm went off and killed him, she had not known it was loaded and attempts to cover up what had happened were because she did not want to lose her children.
Justice Nation thanked jurors for their participation in the trial in what had been trying times, he said.
He said their responsibility was great.
"You were here as representatives of your community, I just say that your community should be immensely grateful and have tremendous respect for you."
Graham was remanded in custody and Hyde remanded on bail to both appear for sentence in the High Court at Invercargill on November 8.
- By Karen Pasco, PIJF court reporter