But in a verdict returned a short time ago, a jury found the teen guilty of a lesser charge, of recklessly causing grievous bodily harm. 

The decision concludes trial that began in Wollongong District Court on Tuesday. 

At issue was whether the 16-year-old intended to cause the devastating harm that resulted after he swung the scooter into the air and brought it down on the head of his 16-year-old victim. 

The attack came as the pair crossed paths in an alleyway in suburban Albion Park the afternoon of April 8 last year. 

The Crown had called on jurors to feel for themselves the weight of the gold-coloured Razor-style scooter, which was tendered as evidence.

Related stories:

"Ask yourself, do you have difficulty lifting that scooter?" prosecutor Emiljia Beljic said, in closing submissions on Thursday.

"Then ask yourself how difficult is it to swing it over and above your shoulder. And if it's difficult to lift, what does that say about the force that was used? And what does the degree of force say about [the accused's] intent?

"I suggest to you that he would have had to exert quite a lot of force to have swung it in the way that he described, and that degree of force hints to the accused having done what he did deliberately and intentionally."

That the teen went for the head - "the most vulnerable part of the body" - also pointed to intent, the Crown had argued.

Ms Beljic called on the jury to see the attack as retaliation for the victim having stepped in to protect his friend from another boy, the accused's 14-year-old friend, in an earlier episode of the conflict. 

But defence lawyer Paul Townsend told the jury his client had no intent and would have pleaded guilty to the lesser charge. 

"This is the first time in a career of a quarter of a century that I have asked a jury to convict my client," he said on Thursday. 

"I'm going to ask you to find him guilty, but not of this crime. I'm going to ask you to find him guilty of the crime he committed, the crime he admits to, the crime he accepts responsibility for."

Mr Townsend said there was no evidence the teen had intentionally swung the scooter at the victim's head.

He focused on the accused teen's comments to police - "I couldn't believe it. I didn't think it would do that much damage" - as proof of a lack of intent. 

"Is that something somebody who had an intention to inflict grievous bodily harm would say?" he said. 

"At that stage he didn't even know how much damage had been done, just that [the victim] was unconscious." 

The victim later underwent emergency surgery for a fractured skull in Wollongong Hospital. He was in a coma for five days and required use of a wheelchair when he awoke. 

The victim and his family were in court to hear the evidence, and for Monday's decision. 

The jury retired at 11.28am Thursday. With the court not sitting on Friday, they returned a verdict 11.25am Monday. 

The matter returns to court on March 28 for the start of sentencing proceedings.