A NSW woman accused of sedating and gassing her grazier partner told police of finding him unresponsive in his bed, saying "I can't get that image out of my head".
"It is killing me," Natasha Beth Darcy said in her police interview played to the NSW Supreme Court jury on Friday.
The 46-year-old has pleaded not guilty to murdering Mathew Dunbar on his property Pandora in the Northern Tablelands town of Walcha in the early hours of August 2, 2017.
She says his death was suicide, while her barrister cited a string of issues including the sheep farmer's confused sexuality, his serious leg problem and depression.
But the Crown says Darcy killed her 42-year-old partner in a bid to inherit his $3.5 million property.
In her recorded police interview of August 4, 2017, Darcy said the grazier had lived on the property all his life while she moved there in 2016 after meeting about three years earlier.
"I was walking in the rain and he gave me a lift," she said.
On August 1, they attended a Tamworth hospital appointment about his injured leg when he was told it would probably not improve and would need an operation, possibly an amputation, in six months.
"Matt came out feeling pretty bad," she said.
They then made various purchases, including a gas bottle.
"He did tell me we have to pick up the bottle of gas for the welder."
Back at home when she and others were dealing with some lambs, "he was almost in tears because he couldn't help" due to his leg.
He said he was concerned he would have to sell the property but she told him she could continue to work under his instructions and no decision had to be made yet.
He asked if she could sleep on the lounge that night which she did to give him privacy after his leg had been kicked in bed the previous night.
Darcy exchanged messages with a friend in which she said Matt was "in a lot of pain" and that she had spent hours talking with him, getting him to see he was actually lucky.
When she went into the bedroom before going to sleep on the lounge at 12.30 am she did not see the gas bottle.
"No, I think I would have noticed that, unless he had it hidden."
She later woke up when smoke was coming out of the fireplace and she used his crutches to turn off both fire alarms.
She opened the bedroom door and "sort of shook" Mr Dunbar who didn't answer .
She turned the bedside lamp on, saw he had blankets up to his head, one eye open and the other closed, and a bag over his head.
"This is the hardest bit of all. I can't get the image out of my head."
Darcy said she heard a hissing sound and turned the gas off at the start of her triple-zero call before commencing CPR.
When the paramedics arrived and moved him off the bed to work on him, they were "very rough and I said be careful".
"I stayed there. I just wanted to touch him. I was holding his leg, his left leg."
After the paramedics declared him dead, she said she screamed at them to "keep going".
The rest of the interview will be played on Monday.
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Australian Associated Press