About 9.30pm on Monday night, police rushed to the family home of anaesthetist Dr Andrew Carll in Rockhampton, Queensland.
They were responding to a frantic triple-0 call: A man had discovered the bodies of Carll, 58, and his wife Julie Rush, 49 in the main bedroom of their Frenchville home.
This call came from a male relative - believed to be one of the couple's three sons.
Queensland police confirmed Rush was the deceased woman on Wednesday. They are yet to formally identify the deceased man, but family and friends have said it is her husband.
Police said a firearm was used, and they are not looking for anyone else in relation to the killings.
On Thursday night, Carll’s sister Mary Carll confirmed her brother and sister-in-law had died in an apparent murder-suicide.
In an emotional Facebook post, she expressed anger at her brother’s actions.
“It appears that my brother killed his beautiful wife Julie and then himself.
“I am now gone from grief to anger, HOW DARE HER, he can kill himself but why take her?”
Mary removed an earlier post where she confirmed the deaths of her "baby brother and his wife" and expressed her love for her brother, who was 17 years her junior.
Mary, who lives in Patea in New Zealand, said her two sisters, her brother and his wife had travelled to Australia to assist with the investigation.
The Australian reported that Carll and Rush had just returned from an extended holiday in the United States and New Zealand and that the doctor had been on scheduled leave since just before Christmas.
He was due to be back at work next week, according to colleagues.
The Daily Mail reported that he worked at Mercy Health and Aged Care and Rockhampton Mater Hospital.
It reported Carll was living with cancer in 2017 but it wasn't known if his treatment was complete.
Rush was an accountant and had studied at New Zealand's University of Otago and Central Queensland University.
The pair had three sons, including one still believed to be in high school.
They are being cared for by family and friends and are "obviously very, very shaken up" according to Detective Senior Sergeant Luke Peachey.
The bodies of Carll and Rush were unable to be moved for days after their deaths, but were transported to Brisbane on Thursday for post-mortem examinations.
"Through statements as well as forensic evidence, we’re getting a closer picture of what’s happened. Until such time as [post-mortems] have been conducted we won’t speculate on any surrounding circumstances," Peachey said.
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