The High Court in Christchurch has heard a recording of a tense exchange between a woman accused of murder and the sister of her dead husband.
Philip Nisbet, 47, was found dead in his bed in May 2009 and his widow Helen Milner, 50, is charged with murder and two counts of attempted murder.
The Crown says Mrs Milner gave him a lethal dose of the antihistamine Phenergan, which he was allergic to, possibly smothered him in their bed after he passed out, and tried to make his death look like a suicide.
The death had been treated as a suicide and it was only after the Coroner released her findings in 2011 a homicide inquiry was launched as police considered some of Mrs Milner's statements and actions suspicious.
On Thursday, the Crown took the unusual step of allowing the jury to hear the recording of the Coronial Inquest held in 2010.
In it, Mr Nisbet's sister Lee-Anne Cartier can be heard telling Mrs Milner that she told two different stories about where she found a supposed suicide note.
Ms Cartier said Mrs Milner first said she found the note in a safe, but later said she found it in a bedside drawer. On the tape, Mrs Milner twice denies that she said she found the note in a safe.
In another recording, Mr Nisbet's father James Nisbet said the signature on the note was not his son's.
Giving evidence on Thursday, Ms Cartier said it was about a week after the funeral that she began to realise some stories didn't add up.
Earlier, two British doctors who attended Mr Nisbet in Christchurch Hospital two weeks before he died told the trial he was highly anxious and agitated when they saw him.
Shamil Haroon and Jamie Strachan gave evidence to the court via video link from England, having seen Mr Nisbet on two separate occasions on 15 April 2009.
He came into the hospital's emergency department in a highly agitated state in the morning and again in the evening complaining of dizziness and nausea, as well as weakness and exhaustion.
Dr Strachan said he told Mr Nisbet that he was catastrophising the illness, before discharging him and telling him to visit his GP within five days.