A EUTHANASIA advocacy group has confirmed a Gold Coast mother and her two daughters had spent months planning their deaths.
The bodies of Margaret, Heather and Wynette Cummins were found in one of their homes following an apparent triple suicide pact on Tuesday.
Euthanasia advocate Dr Philip Nitschke said he did not personally know the women but confirmed they had joined his Exit International group six months ago.
"They were not terminally ill people but on the other hand, they were not in the best of health either," Dr Nitschke said, speaking from Amsterdam on Wednesday.
"They were obviously working out what they wanted to do."
Dr Nitschke said three members had never ended their lives at the same time before, however it appeared to be a "rational and informed choice".
Their decision to end their lives because of their health problems was a matter only for them, he added.
His comments come as it emerged the women bought deadly gas from Dr Nitschke's "home brewing" company, the Courier Mail reports.
"This didn't happen on the spur of the moment - a lot of planning went into it," Dr Nitschke said.
He told The Courier Mail the gas the women used could be used for brewing beer "or for dying", but didn't believe he would face any legal action because the purchase was "legit".
The gas the women used could be used for brewing beer "or for dying", he said.
The partner of one of the women made the grisly discovery about 3.30pm - and the tragedy has horrified the community, which is one of Australia's most exclusive.
Renting a luxury villa on Ephraim Island can set you back $1000 a week.
Detective Senior Sergeant Mark Procter, the officer in charge of Coomera Investigation Branch, said it appeared to be sad ending to the lives of the three women.
"There are no suspicious circumstances, there are no offenders outstanding and no one in the community needs to feel worried about their safety," Snr Sgt Procter said.
"It's an isolated incident."
He said the partner who found the bodies was understandably upset, but not completely surprised by the tragic scene he discovered.
"He is pretty shaken," he said.
"He wasn't aware that this was culminating today, but he wasn't surprised that it has happened."
He would not comment when asked about the gas link.
One Ephraim Island resident told The Courier-Mail she feared the worst after hearing the news and trying in vain to contact one of the daughters, named Heather, with whom she socialised.
The woman said the elderly mother lived with and cared for Wynette, who was disabled, in a ground floor unit they owned, while battling her own health problems.
The other daughter, Heather, and her partner had recently bought a unit in the neighbouring building to be closer to her family and help care for her sister.
Wynette recently underwent brain surgery but never recovered and it also hit her mother hard, the resident said.
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