An elderly couple died of carbon monoxide poisoning caused by a butano gas cylinder in Rincon de Seca, Murcia.
The odourless and colourless gas eliminates oxygen quickly in human bodies, leading to death.
A neighbour alerted emergency services after not seeing the couple for a few days.
Police broke into their home and discovered the bodies of a man, 74, and a woman, 85.
Early conclusions were that they were not victims of an assault with no injuries sustained on their bodies.
Subsequent autopsies confirmed that they died from gas poisoning.
The state of the single-storey property was poor with filled-up bags and old belongings strewn everywhere.
The lack of adequate ventilation may have contributed to their accidental deaths.
The advice for any gas device that is used indoors is that it must be placed in a well-ventilated area.
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