A Sydney GP accused of injecting his wife with a lethal dose of insulin said he left home after an argument and when he returned she was dead.
Brian Kenneth Crickitt told detectives he left the couple's Woodbine home in Sydney's southwest about 2am on New Year's Day 2010 after an argument in which his wife Christine accused him of having an affair.
He said when he returned about 8.15am she was dead in their en suite.
"I saw her lying on the floor, just sort of slumped face down on the floor," he told police that night in a video-recorded interview, which was played at his NSW Supreme Court trial on Thursday.
"She was obviously dead. She was cold."
Crickitt, 63, sniffled into a handkerchief and appeared emotional at times during the interview, while breaking into nervous laughter at other times.
The prosecution alleges he injected Mrs Crickett, who was not diabetic, with fast-acting insulin so he could claim her life insurance worth $568,000 and be with Ms Livermore.
On Thursday, the court heard police found a screenshot of a Google search for "insulin overdose" among electronic files copied from Crickitt's computer.
His former patient Kristina Mitchell, a diabetic, testified that she received and filled a prescription from the GP for slow-acting insulin dated December 31, 2009.
Crown prosecutor Mark Tedeschi QC showed her a prescription from Crickitt made the same date for fast-acting insulin.
She said the signature on the prescription wasn't hers.
In the police interview Crickitt initially said he'd gone for a drive in his BMW and fallen asleep but that evening admitted he'd gone to see his lover Linda Livermore, a meditation teacher and former patient.
Crickitt said his relationship with his "volatile" wife had become difficult and he and Ms Livermore had discussed a future together.
He denied drugging his wife and, asked how he thought she died, he replied, "I don't know", adding she'd previously mentioned she'd been thinking of "taking some pills".
"I don't think she would do a thing like that," he said.
Crickitt has pleaded not guilty to murder and appeared in court supported by his new wife Julie.
The trial is continuing before Justice Clifton Hoeben without a jury.
