Carbon monoxide poisoning is suspected to have killed three family members found dead at the bottom of a concrete water tank in New South Wales, Australia.
Police said a 69-year-old man was using a high-pressure water pump to clean inside the tank yesterday evening on his property in Gunning, near Yass, when he collapsed.
The man's brother, 68, and the man's wife, 63, jumped into the tank to try to help, but also collapsed.
A neighbour who heard the woman's cries for help found the three bodies and called emergency services.
NSW Police Superintendent Andrew Koutsoufis said the deaths appeared to be a tragic accident.
"There were high levels of poisonous gas in the water tank by the time police got there," he said.
"A petrol [water] pump being used the clean the tank may have been the cause of the build up of fumes at the bottom of the tank."
Superintendent Koutsoufis said post-mortems would be needed to confirm the cause of death.
"Carbon monoxide poisoning is a line of enquiry we are following," he said.
Police said the family of the deceased had been told, but they were not expecting to make the names of those who died public today.
"They just need some time to grieve," Superintendent Koutsoufis said.
"It's devastating for a small community like Gunning. A lot of people are hurting right now."