Dr Andrew McIntosh, an experienced biomechanist, was among the last witnesses to take the stand on week three of Constable Rolfe's murder trial on Friday.

Dr McIntosh had been provided with body worn-camera footage from Constable Rolfe and Remote Sergeant Adam Eberl at the time of the shooting, and asked to provide an opinion as to the threat Mr Walker posed to the two officers at various points throughout.

He said at the time the "first incident" - when all three men were still standing and Mr Walker had just pulled out a pair of scissors - he did not consider Mr Walker to be a major threat to Constable Rolfe.

"On balance, at the time Rolfe first shot Walker, Walker was unlikely to be a direct threat to Rolfe," Dr McIntosh wrote in his report.

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"Immediately prior to the first gunshot, Rolfe was separated from Walker."

"Walker may have been a direct physical threat to Eberl [at that time] because of the scissors."

However, Dr McIntosh noted, "The body-worn evidence regarding this threat and the presence of the scissors is inconclusive."

Constable Rolfe's lawyer David Edwardson QC has previously told the court Mr Walker stabbed his client in the shoulder with the scissors in the moments before firing the first shot.

Almost immediately after the first shot had been fired, Sergeant Eberl wrestled Mr Walker to a mattress on the floor, pinning the arm Mr Walker was holding the scissors with under his body.

Dr McIntosh said that during this time, Sergeant Eberl would have been able to press about half his total body mass onto Mr Walker's chest.

Because of this, he said in his report, Mr Walker was "unlikely to be a direct threat to Rolfe" at this time and he was likely a "low level threat to Sergeant Eberl".

However, Dr McIntosh said it was impossible to know exactly how much the movement of Mr Walker's right arm was restricted as it was not visible in the footage.

"If it was a whole arm, then it would be very restricted. If it's the upper arm only, then it's still restricted, but not as restricted as if it was the whole arm under the side."

In cross-examination by Mr Edwardson, Dr McIntosh agreed the level of threat perceived by the officers at the time of the incident could have been different to his analysis.

"Would you accept that, of course, neither officers Eberl or Rolfe had the luxury of being able to slow things down frame by frame? They, of course, were dealing with this situation, this dynamic situation, in a matter of seconds," Mr Edwardson asked.

Dr McIntosh replied, "That's correct."

Forensic pathologist Dr Paull Botterill told the court in his evidence on Friday that he believed the injury Constable Rolfe sustained during the scuffle was "consistent with being stabbed by scissors".

"I can't say it was necessarily that specific pair of scissors, and I can't say that it hadn't been some other implement that may also have a sharp point on it," Dr Botterill said.

Crown prosecutor Philip Strickland SC told the court he intends to call three more witnesses, with the prosecution case likely to finish on Tuesday.

It is unclear at this stage whether the defence will call its own witnesses to give evidence before closing statements.