This story discusses graphic details of evidence relating to the murder of Susan Burdett
The Crown has closed its case against serial rapist Malcolm Rewa - with its final witness detailing the fatal injuries of his alleged murder victim.
Susan Burdett, a 39-year-old accounts clerk, was raped and clubbed to death in her Papatoetoe home in 1992.
Rewa has been tried twice for her killing but juries in two separate trials were unable to decide if he murdered her.
Today the Crown called its last witness, Dr Simon Stables, who reviewed the post-mortem examination carried out by Dr Timothy Koelmeyer.
The pathologist said the report suggested Ms Burdett was forcefully stuck on the head and would have died in minutes.
"Dr Koelmeyer says 'I believe that the deceased was struck at least five blows to the head with a heavy implement; the blows being delivered from the general direction of the left side of the deceased'.
"The injuries to the skull and brain are of such severity as to have been necessary and rapidly fatal."
Rewa was convicted of raping Ms Burdett in 1998.
His DNA was found inside her when she died but it wasn't until four years later that it was identified as his.
The Crown's case is that Rewa murdered Ms Burdett during the course of this sexual assault with a baseball bat she kept for her own protection.
A wooden baseball bat found next to her body has sat in a glass box at the front of the courtroom, labelled Crown exhibit five.
This afternoon Crown prosecutor Gareth Kayes asked Dr Stables if he could conclusively say it was the murder weapon.
"You can't get exact. All you can do is give an opinion as to whether this particular instrument is consistent or not. Certainly a baseball bat, given the nature of the fracturing, would be consistent."
Dr SallyAnn Harbison, a forensic scientist at ESR, had previously told the court she examined four small blood spots - invisible to the naked eye - found on the bat.
But she said the test results were inconclusive, meaning there was no forensic evidence connecting the bat to Ms Burdett's killing.
Dr Stables said a bruise to the back of Ms Burdett's left hand was consistent with a defence injury.
"This is absolutely classic for a defence injury.
She has tried to protect herself and rather than the body or the head taking the blow the back of the hand has."
He said an important observation made by Dr Koelmeyer was the weight of Ms Burdett's lungs.
"Someone who has a significant head injury, if they survive for a period of time, gets fluid built up in the lungs.
"The result of that is the lungs at the autopsy will weigh quite a bit; they're a lot heavier.
"He's not noted that at the autopsy, in fact the lungs weighed normal, which actually supports the proposition that this woman actually died very quickly. And when I say quickly I mean within minutes."
He likened the force applied to Ms Burdett's head - which fractured the base of her skull - to that seen in car crashes.
"I think this has required a significant amount of force.
"The skull itself is not uniform in its thickness, but to fracture through the base of the skull requires a significant amount of force.
"In fact that injury, that fracture through the base, is something that is more commonly seen in car accidents so you can imagine the force involved in that."
Under cross-examination, Rewa's lawyer Paul Chambers questioned Ms Burdett's time of death - estimated by Dr Koelmeyer to be 11pm on Monday, 23 March 1992.
Dr Stables said he could not determine the time of death based on the information he had, describing as a "difficult".
He said the only definitive way of working out the time period in which someone had died was finding out when they were last seen alive and when their body was found.
"That seems to be fairly obvious but those are the only two definitive pieces of information available. Everything else is based on circumstances."
Mr Chambers previously accused Ms Burdett's son, Dallas McKay, of murdering his mother to gain a $250,000 inheritance.
The defence will open its case on Tuesday.