The Court of Appeal has reserved its decision on the case of Christchurch woman Helen Milner, found guilty of murdering her husband by poisoning him with pills to which he was allergic.
Milner was jailed for life earlier this year and ordered to spend at least 17 years in prison for poisoning Philip Nisbet in 2009.
Mr Nisbet's death was initially treated as a suicide, but after an investigation by his sister Lee-Anne Cartier and an inquest the case was reopened in 2011.
Milner poisoned Mr Nisbet with an overdose of an antihistamine to which he was allergic in order to get his $250,000 life insurance payout.
Her lawyer told the Wellington court on Thursday that Mr Nisbet must have tasted the pills if they'd been put in his dinner and there was also a possibility he could have taken the pills himself.
But the Crown said the pill evidence was part of a strong circumstantial case, which included forged suicide notes and Milner's son seeing her crushing up pills and putting them in capsules.
Outside court, Lee-Anne Cartier rubbished the suggestion made by Milner's lawyer. She said few men would tell their wives they found a meal unappetising, and her brother was not the sort of man who would have offended his wife.
Ms Carter said the appeal hearing was a waste of taxpayers' money and very stressful.
The investigation was costly for Ms Cartier and she believes police are dragging the chain in deciding whether she should be compensated for her efforts on behalf of her brother.
She said she hopes the matter is resolved while her parents are still alive, so she can repay money she borrowed from them in order to do her investigation.