It is caused by the bacterial decomposition of organic matter that has died and sunk to the bottom.
FORBES: How Could You Possibly Have A Problem With Diesel-Based Gas Fracking?
However, tests that might have revealed unusual or volatile poisons were ruled out by the decomposition of the body.
The decomposition of Williams' body was hastened by the fact it was in a top floor apartment, where the temperature soared in the summer heat.
"It will be an unknown location in the open desert, " he said, adding that a burial was needed because decomposition of the body had reached the point where the "corpse cannot last any longer".
He said because of the decomposition of the body the informed cause of death was unascertainable but taking into account the case as a whole, some kind of suffocation or chest compression was most likely.
BBC: Stuart Hazell leaves his partner's house on 8 August 2012
Last year a Dutch study found that draining Indonesian swamps to make way for oil-palm plantations resulted in 33 tonnes of carbon dioxide emissions for each tonne of palm oil produced, by speeding up the decomposition of the peaty soil.
The body of Carmelita Stevens, Murphy's girlfriend, was found in a state of decomposition.
Across the farm, there were numerous animal carcasses in various states of decomposition.
In the bedroom of the apartment, officers discovered the body of a woman "in a state of decomposition, " the statement said.
The experts are still trying to identify a further 10, 000 remains, but their advanced state of decomposition makes it a slow task.
He also said the rate of decomposition for bags varied depending on the environment they were left in and therefore a single date for labelling would be hard to determine.
In mammals, the structure of many of these decomposition products - with evocative names such as cadaverine - is known.
BBC: Hidden graves found using chemical 'sniffer' technology
Their detection technique accurately spotted the presence of the cadavers, at times ranging up to 20 weeks after burial - the decomposition process eventually exhaust the supply of proteins.
BBC: Hidden graves found using chemical 'sniffer' technology
They will measure the amount of carbon, phosphate and nitrate in the soil, together with the rate of plant growth and microbial decomposition.
应用推荐