Lee-Anne Cartier became a self- appointed detective in her quest to find the truth about her brother's death, a jury has been told.
She believed Helen Milner killed him - despite police saying his death was a suicide - but sympathised with her in "the hope that she would let something slip".
Ms Cartier had become suspicious of Milner after she showed her a typed suicide note complete with a hand-written signature she did not recognise as her brother's.
"It didn't add up," she said yesterday.
Under cross-examination, defence counsel Margaret Sewell put to Ms Cartier: "You became a self- appointed detective".
Ms Cartier agreed. "My brother had died and I needed to know the truth and I think anyone in this room would have done the same thing too."
The evidence emerged during day five of a three-week trial in the High Court at Christchurch.
The jury was told that after Cartier became suspicious about the death of Philip James Nisbet she began contacting people who might have any information she could give to police.
Mr Nisbet's son, Ben Porter, also gave evidence that his father, a truck driver, was excited about a new route he was due to start the day his body was found. His father was no good with technology and did not know how to use a computer very well, he said.
Milner, 50, is charged with the murder and attempted murder of her husband.
Mr Nisbet, 47, was found dead in bed at the couple's Checketts Ave home in Halswell on May 4, 2009.
The Crown alleges Milner drugged her husband by mixing Phenergan with his food and then may have suffocated him while he was sedated.
Ms Cartier began contacting Milner's former colleagues at Christchurch company Grounds & Services about four months after her brother's death.
Lynette Maynard told her she heard Milner talking about rat poison and killing someone.
Ms Cartier passed that information on to police. She also spoke to Milner's neighbour Raymond Carey, who told her his wife had seen a bedroom light on next door on the morning Mr Nisbet's body was found.
On a trip to New Zealand, Milner gave Ms Cartier, who lived in Queensland at the time, Mr Nisbet's phone to use.
Ms Cartier copied all the numbers off it and gave them to police.
She then contacted anyone who might be associated with the case.
Ms Cartier told funeral director Glen Rossiter-Campbell she believed Milner killed her brother. Ms Sewell said this "contaminated" his evidence.
She put to Cartier that she had downplayed an incident where Mr Nisbet jumped in a pool many years before his death, because she didn't want people to think he was being suicidal.
Ms Cartier disagreed.
"He would do little attention- seeking things but not kill himself."
Mr Porter, Mr Nisbet's son from a previous relationship, told the jury he did not see his father often but they got along well.
He spent time with his father two days before his death. Mr Nisbet was excited about a new trucking route to Kaikoura he was due to start.
"He . . . had always wanted to do that run." Fairfax NZ
- © Fairfax NZ News
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