When Roland Wessling looked over to his partner Hazel Woodhams he knew instantly that she was dead. What he didn't yet know was that her killer was still in their tent, and that his life was also in danger.
Carbon monoxide, a colourless, odourless gas, had leaked from their extinguished barbecue. Hazel and Roland had been poisoned as they slept.
Half of the world's population use basic carbon-based fuels such as coal, wood and dung to cook and heat their homes, often in poorly ventilated spaces.
The dangers of being too close to an open fire are clear to most of us, but what many people don't know is the potentially fatal threat of a carbon fuel fire that is no longer burning.
Silent killer
In 2011 Hazel and Roland took up camping and bought a new tent. Hazel turned 30 and they decided to take a short trip to the Norfolk Broads for a weekend of camping and canoeing.