Matthew Henry Spinks was "emotionally unravelling" following a stabbing that "eviscerated" him when he fatally shot his friend Nathan Costello, a Supreme Court sentencing hearing has been told.
A jury found Spinks guilty of Mr Costello's murder in February. The jury heard Spinks, 35, fired two gunshots from his slow-moving car through Mr Costello's parked car in the early hours of February 14, 2018 in Carr Parade, Unanderra.
Justice Peter Hamill presided over his sentencing hearing at Wollongong on Wednesday.
"Things changed for the offender after he was stabbed in August 2017," Spinks' defence said.
"It was a visually shocking injury that required surgery and time in intensive care."
Spinks' defence said after the injury his use of drugs, in particular ice, increased.
As a result, he became paranoid and "his ability to think things through was lessened".
Following a dispute, Mr Costello had entered Spinks' home armed with a knife on February 5, 2018 and threatened him, although he did not harm him.
"For the deceased to enter the offender's home with a knife, in the context of the offender being eviscerated with a knife outside his home only a few months before ... there was a feeling of betrayal," the defence said.
As part of the proceedings Justice Hamill received a letter from Mr Costello's partner, detailing the impact the murder had had on her and their children.
"I understand there is nothing I can do or this court process can do to ease the pain your are suffering now and perhaps forever, nothing I can do to bring him back or take away the loss of two children's father," Justice Hamill said.
"I am very grateful for you providing this letter to offer some insight into what you are going through. I remember when you gave evidence feeling your pain to some extent."
Spinks is scheduled to be sentenced on June 10.
We depend on subscription revenue to support our journalism. If you are able, please subscribe here. If you are already a subscriber, thank you for your support.