From that link discussed above:
"Abstract
Police in the UK received information that a person had been reported as missing. Despite a diligent search and investigation, the person was not found. Several years later police received intelligence giving the location of a grave believed to contain the remains of the person previously reported as missing and now believed to be a victim of homicide. This new information suggested the missing person had been murdered and their remains were buried in a shallow, unmarked grave. Following a systematic search, the murder victim's body was found at a shallow depth, less than 1 m. Following the forensic recovery of the body, soil samples were collected at, beneath the floor of the grave, along the strike of the grave, downslope and upslope. Analysis of the soil samples showed elevated levels of putrescine, at nearly 150 ppb in the soils beneath, downslope and for several metres upslope from the body at localities where detector dogs had showed an ‘interest’ before the grave was discovered. The mineralogical analysis, using integrated automated mineralogy and petrology detected the presence of diagenetic calcite in the soil profile beneath the grave. Additionally, the organic analysis detected the presence of elevated stanols at the grave and down slope."
Some new words for me:
"diagenetic calcite"
"stanols" and "Stanol Ester"
Esters. Esters are polar molecules, but their boiling points are lower than those of carboxylic acids and alcohols of similar molecular weight because there is no intermolecular hydrogen bonding between ester molecules. ... Acids have unpleasant smells, but esters have fruity smells.
"diagenetic calcite" seems to form during the process of rock formation. No mention of odour production.
It could be that the cadaver dog smells a combination of cadaverine/putresciene and stanol esters to give a species specificity to their work.