A man accused of murdering his wife, who used a wheelchair, by throwing her into a pond seemed "quite calm" and "unfazed" when emergency crews arrived, a court has heard.
Peter Rex Dansie, 70, went on trial in Adelaide's Supreme Court after pleading not guilty to murdering his wife Helen in April 2017.
Prosecutors allege Mr Dansie threw his wife into a pond in Veale Gardens in Adelaide's southern parklands because she had become a burden to him.
Paramedic Richard Giles told the court when he arrived at the scene Mr Dansie appeared calm and did not have any sense of urgency.
"He seemed quite calm, he didn't appear too upset or too panicked," he said.
"Almost a bit deflated, like he was exhausted."
The court heard Mr Dansie's clothes were wet from his waist down and he told paramedics his wife had been in the pond for about 25 minutes.
"He said he had been in there trying to get her out but wasn't able to," Mr Giles said.
"He said he tried to turn the wheelchair around, he wasn't able to, he asked the patient to take the brakes off and as she did that the wheelchair rolled into the pond."
Mr Giles told the court resuscitation would not have been successful because Mrs Dansie had been submerged in the water for too long.
During his evidence, investigating officer Sergeant Philip Clague told the court the accused did not appear distressed when police arrived either.
"His behaviour and demeanour didn't seem in line with someone whose wife had just drowned," he said.
"He was very calm and seemed unfazed by it all."
Alleged murder was financially motivated
In opening the trial on Tuesday, prosecutor Jim Pearce QC said Mr Dansie climbed into the pond after his wife to "feign an attempt to rescue her".
He said the alleged murder was premeditated and financially motivated.
"Helen Dansie had become a cost burden on the accused, it was a cost burden he was no longer prepared to tolerate," he said.
The court heard Mrs Dansie, a former microbiologist, suffered a stroke in the 1990s that left her with long-term disabilities.
It heard she was on an indexed pension for life of which a large portion her husband was entitled to as her full-time carer.
The trial before Justice David Peek, without a jury, continues.
