But who brought the gun to Salt Ash on the afternoon that David King was shot dead?

Was it Elijah Cage and Max Lowcock, the two men accused of murdering Mr King, who brought the gun as part of an alleged plan to rob the mid-level drug dealer of half an ounce of methamphetamine.

Or was it Mr King who had the gun all along?

It is a question the jury in the murder trial of Mr Cage and Mr Lowcock will have to answer when they retire later this week to begin deliberating.

The prosecution say the two men, as part of their plot to rob Mr King, brought the gun with them to the meeting in Hideaway Drive and introduced it into Mr King's car in the moments before he sped down the road, swerving back and forth in an attempt to flee an alleged drug rip, and was shot in the head.

But during her closing address on Tuesday, defence barrister Leah Rowan, for Mr Lowcock, told the jury the evidence pointed to Mr King having the firearm before the fatal drug deal.

Police found video of a woman with connections to Mr Cage holding the firearm the night before the fatal shooting, but she told the jury that it was Mr King who had the gun and he let her hold it to film the video.

Crown prosecutor Liam Shaw called the woman's evidence "completely unbelievable", but Ms Rowan said she had answered every prosecution question about where she got the gun.

"It is clear on the evidence that Mr King had involved himself in the supply of drugs at a fairly significant level and... things for him were spiralling in the last few weeks before August 29," Ms Rowan said.

"You might want to consider whether David King had armed himself with a sawn-off shotgun. It is Mr King whose state of mind leading up that date most lends itself to the fact that he would be in possession of a gun."

Ms Rowan said the question of who brought the gun was "wide open" and the prosecution would need to rebut the possibility that Mr King had the firearm and prove beyond reasonable doubt that it was Mr Cage or Mr Lowcock who brought it to the drug deal.

"And members of the jury, in my submission, they can't do that," Ms Rowan said. "They can't prove that to you beyond a reasonable doubt because of the evidence of [the woman] and to the extent that it can be corroborated by the video."

Ms Rowan said the key witness - who set up the drug deal, witnessed the shooting and then claims she was kidnapped by the men - gave evidence that she did not see either Mr Cage or Mr Lowcock introduce the gun into Mr King's car.

And that witness said that, after Mr King took off with the two men on board, swerving back and forth before he was shot and the car careered into a tree, she ran down the road to see what happened.

"She says to you, 'I didn't know who was shot'," Ms Rowan said of the key witness. "You don't know who was shot because you don't know who has a gun and you don't know who has a gun because you didn't see a gun. And in those circumstances there is no way she could have missed it if it was either of the accused that brought that gun into the car. No way. I don't need to prove to you that it was Mr King who produced the gun. The accused don't need to prove anything but the evidence that you've got all points in my submission one way and that's that Mr King had that gun."

The two men remain charged with Mr King's murder after Justice Dina Yehia on Monday directed the jury to acquit the driver Tyson Stamp, ruling there was insufficient evidence to establish that he was guilty of murder.

The three men are all still charged with kidnapping the woman who facilitated the drug deal and witnessed Mr King's shooting and their trial in Newcastle Supreme Court is nearing an end after four weeks of evidence.

The closing addresses will continue on Wednesday before Justice Yehia sums up the evidence and sends the jury out to begin deliberating.