Darren Wilson's defence barrister Tom Danos said in his closing address to a Supreme Court jury on Tuesday that DNA and blood splatter analysis would also prove damaging to the prosecution's case.

"Not only are they (witnesses) largely contradicting each other, they're not actually supported, we would submit to you, ultimately by the DNA evidence and the blood pattern evidence that's been put before you," Mr Danos told the jury.

"Despite the Crown disavowing any real interest in the DNA and blood pattern material, we actually say to you that is the vital evidence in this case."

Wilson is standing trial in the Supreme Court having pleaded not guilty to the murder of Timothy O'Brien, 14, who was allegedly killed with an axe at a Scarsdale house in the early hours of January 5 last year.

EARLIER IN THE TRIAL:

The Crown in their closing told the jury Wilson was a violent liar who couldn't be believed, adding he was guilty of murder and four charges of inciting others to murder.

Timothy's body was found at a Scarsdale house on the morning of January 5 last year.

The jury has heard Wilson and a 16-year-old girl living at the house devised a plan to lure Timothy's stepfather, Peter Williams, to the house and bash him.

Mr Williams and Wilson are cousins and the jury has heard their relationship had soured in the weeks leading up to Timothy's death.

Mr Williams was allegedly jumped by Wilson when he arrived at the Scarsdale house in the early hours of January 5. 

Timothy used a baseball bat to defend his stepfather before he was allegedly chased out of the house by another man who allegedly used the blunt side of an axe to hit Timothy repeatedly in the head.

Wilson is accused of then grabbing the axe, turning it to its bladed side, and continuing to strike Timothy.

The trial, now in its sixth week, continues before Justice Betty King.