A former university colleague says murder-accused Clayton Weatherston told him about problems with his relationship in the days before he killed his ex-girlfriend.
Mr Weatherston, 33, denies murdering student Sophie Elliott. He has admitted a charge of manslaughter.
Miss Elliott, 22, was stabbed to death 216 times with a knife and scissors at her home in Dunedin on 9 January last year.
The defence says Mr Weatherston's personality and anxiety disorders meant he was unable to cope with the volatile relationship and he was provoked when Miss Elliott lunged at him with a pair of scissors.
Dorian Owen, a professor of economics at the University of Otago, told the court on Friday he had known Mr Weatherston since 2001 and thought he was laid-back and had a good sense of humour.
Mr Owen said the accused, who was a tutor, had an excellent academic record, but there were some in the economics department who found him arrogant and he had a degree of ultra-competitiveness.
Professor Owen said he thought Mr Weatherston's relationship with Miss Elliott was a bad idea and that the accused had not thought through the consequences of having a relationship with a student.
He says Mr Weatherston met with him twice in the days before Miss Elliott was killed, and told him about problems they were having.
He says the accused told him Miss Elliott had broken the glass in his front door and was using attention seeking behaviour to try to make him jealous.
Professor Owen advised Mr Weatherston to keep his head down and to leave Miss Elliott alone.
But he says he got the sense from the accused that he needed to have the last word because it was part of his personality.
Professor Owen told the court Miss Elliott was an excellent student who was forceful, lively and spoke her mind.
The trial was delayed for legal discussions on Friday morning and resumed after lunch.