The Ashburton Work and Income murder trial has heard Russell Tully tried to wrench open a police dog's mouth and gouge its eyes when he was being arrested.
Mr Tully, 49, is on trial for the murders of Peggy Noble and Leigh Cleveland and the attempted murders of two of their colleagues at the office.
Today marks the sixth day of the trial in the High Court in Christchurch; the accused, Mr Tully, was not present in court.
A police dog handler, Reuben Whalley, told the court he was driving to the Lake Hood area when he noticed a mountain bike sticking out of a hedge.
Mr Whalley said he pulled Mr Tully out of the hedge by his boot.
He said Mr Tully tried to wrench the dog's mouth open and was poking at its eyes.
Earlier, chief forensic pathologist Martin Sage read parts of his medical report into the deaths of Ms Noble and Ms Cleveland to the jury.
He said when he conducted an autopsy on receptionist Peggy Noble 158 shotgun pellets were found in her chest.
Dr Sage said Ms Noble died immediately.
"The blast passed into her upper central chest, demolishing the upper third of the breast bone, many pellets had passed through the major blood vessel at the base of the heart, the aorta."
Dr Sage also read out details about the death of Leigh Cleveland who was shot three times.
He told the court the third shot was fatal.
"The fatal discharge was that of a shot gun slug which had passed through her right shoulder, with her right arm elevated up towards her head, passing through the upper part of the breast bone demolishing it, it then went though the heart."
Details of arrest
Today the court also heard details of how the accused, Mr Tully, was arrested.
Police dog handler Reuben Whalley told the court he was driving to the Lake Hood area to look for the offender when he noticed a red mountain bike sticking out of the hedge.
'I let my dog Luka out on an extended leash and she signalled a lot of interest in the area."
Mr Whalley told the court he could not see the offender but by the dog's reaction could tell he was in the hedge.
"I then yelled out a challenge 'police dog handler - I have a dog, come out now or the dog will be deployed or the dog will bite you.'"
He said when there was no response he let the dog still on a leash into the hedge.
"I heard the offender scream when the dog bit him and I could tell the dog was engaged with him."
"We couldn't see him or if he had anything with his hands, but his boot was visible so I reached down and pulled him out of the hedge by his boot.
"I could see he was struggling with the police dog he had his dog's head trying to wrench his jaws open, he was also poking at the dog's eye area," Mr Whalley said.
Earlier in the day a farmer, who spotted a man on his property following the WINZ shootings, told the jury his instincts kicked in straight away.
Farmer tells court how he called the police
Farmer Daniel White told the court he was working on his farm on the outskirts of Ashburton when he saw a man carrying a bicycle on his shoulder.
"I was already aware of what had happened in town prior to this - so instincts, straight away. It was a man, carrying a bike. I didn't want to go anywhere near him."
Mr White said he drove away from the man and called the police.