A King country shearer who went on a crime spree, assaulting and threatening to kill numerous people, was insane at the time and thought he was a trained assassin, his defence team has argued today.



Te Rangi Jamie Charl Trangmar, 27, who also goes by the surname, Marshall, pleaded not guilty by reason of insanity when he appeared in the Hamilton District Court this morning on 17 charges.



The charges, which include aggravated robbery, kidnapping, assault, injuring with intent, threatening to kill and wilful damage, occurred on three separate dates in 2010.



The first occurred in July when he allegedly held his former partner captive and during that time repeatedly punched her in the head and smashed her head against a wall.



The later charges, over two days in September, made national headlines at the time after an allegedly armed Trangmar shot up Curly's Bar in Waitomo before being wrestled to the ground by patrons.



He managed to escape, before trying to run two of them down with a quad bike he'd illegally taken from a friend.



Opening the case for the defence this morning, lawyer Roger Laybourn said this wasn't a case of "who done it, but a why done it".



The "frightening" facts of the case weren't disputed, he said.



"What is disputed is his mental state at the time.



"The defence is saying that he was so mentally disturbed at the time that he was incapable of forming a criminal intent."



After his arrest Trangmar was seen by several psychiatrists who found he was suffering delusions, he said.



He told them he was a SAS member and a trained assassin and that people in the Otorohanga community were plotting against him.



He also claimed that he was Hitler's grandson and had swastikas tattooed on his face because of it.



After his arrest Trangmar spent time in the Henry Rongomau Bennett centre, at Waikato Hospital, before was fit enough to even plead to the charges because his mind was so messed up, Laybourn said.



However, Crown prosecutor Tini Clark said Trangmar did know what he was doing at the time.



"He understood that what doing was legally and morally wrong," she said.



"It does not reach the threshold of defence of insanity."