We do have a report on what chemicals were found in the air that "off-gassed" from a sample of the carpet from the trunk of the car, after the carpet sample was kept in a sealed container for a period of time. 6 of the chemicals found in the carpet sample air met the following conditions: (1) they are associated with human decomposition, (2) they were also found in a sample from a blanket that had held a decomposing 3-year old child kept in the trunk of a car in a Montana case, (3) they were not found in a carpet sample from another car of the same make and model, (4) they were not found in a sample of the air from the white trash bag, which means they could not be accounted for by any of the items in the trash bag, (5) they were not found in a sample of the air from the passenger area of the car, (6) they were not found in the air of the laboratory that was performing the tests, (7) they were not found in the air of the OSCO forensics garage, (8) they were not found in gasoline, which accounted for many of the other chemicals found in the carpet sample, (9) they were not found in decomposing pizza.
In addition, carbon tetrachloride, which is found in human decomposition but not in animals that have been tested, was found in the trunk carpet. A trace of carbon tetrachloride was also found in the air from the trash bag, but of course the paper towels with potential decomp residue were also in the trash bag. No trace of carbon tetrachloride was found in the sample of carpet from the similar car, in the passenger area of the car, in the laboratory air, in the decomposing pizza tested by the lab, in gasoline vapors tested by the lab, or in the OSCO forensics garage. Moreover, no carbon tetrachloride was found in the air "off-gassed" from a carpet sample on which a squirrel was allowed to decompose.
Chemicals that would have been expected if an animal (rather than a human) had decomposed in the trunk were
not found in the carpet sample.
Butyric acid was found in scrapings from the carpet. This acid is a product of human decomposition. It is also found, for example, in rancid butter, but there is no other indication of the presence of butter in the trunk.
http://i.cdn.turner.com/cnn/2009/images/06/19/6551.6591.pdf
