Let’s talk about how long Laci’s corpse was in the water. VOS says in his latest blog entry:“Laci Peterson could not have been in the sea for more than 14 days at the extreme outside. 16 weeks is impossible - there would remain only a few scattered bones of hers and nothing of the baby.” He links to a very good and appropriate study here called TR-09-2002.
If you read the actual study, you can see it contradicts the claim made in the opening quote. In fact, it even shows a picture from the Fall experiment of a largely intact pig brought out of the water at 35 days. So what other literature is out there on time of death determination in bodies recovered from saltwater?I don't agree with VOS that Laci was in the water 14 days at the extreme. Evelyn Hernandez was missing 85 days and her remains were much more disarticulated than Laci's (112 days post mortem). Both women had adipose tissue on the thighs and buttocks. VOS seems to be ignoring the adipocere which takes weeks or months to form.
Estimating the post-mortem time period is by no means an exact science -- only a range can be determined, and that might not be 100% accurate as all conditions to which the body was subjected might not be known. Galloway gave a 3-6 month estimate. Interestingly, 3 months allows for Laci to still be alive as late as mid-January.
We've consulted a couple of sources to gain an understanding of the decomposition process, and especially for aqueous environments.
Forensic Taphonomy: the Postmortem fate of Human Remains by William Haglund and Marcella Sorg, 1996. Click here for a list of all the chapters. Of particular interest are chapters 29, 37 and 38. You can copy the chapter titles into a google search and then should be able to access the entire chapters.
An Experimental Field Protocol for Investigating the Postmortem Interval Using Multidisciplinary Indicators, by Kenneth Schoenly, Ph.D.; Karen Griest, M. D.; and Stanley Rhine, Ph.D., found in Journal of Forensic Sciences, JFSCA, Vol. 36, No. 5, Sept. 1991, pp. 1395-1415.
Color Atlas of Forensic Pathology by Jay Dix. It's exactly what it says -- a color atlas, meaning lots and lots of photos that are very gruesome. Not something to read over lunch.
"Disappearance of Soft Tissue and the Disarticulation of Human Remains from Aqueous Environments," William Haglund, Journal of Forensic Sciences, JFSCA, Vol. 38, No. 4, July 1993, pp. 806-815.
There is some research ongoing on using Accumulative Degree Days (ADD) or Cumulative Degree Hours (CDH). Click here for the source for the following, which provides information on using the presence of the decomposition chemicals to help determine PMI, but that wasn't done in Laci's case.
Accumulated Degree Days (ADDs), as described by Edwards etLaura Ayers used ADD in her experiment, which is another very valuable read: DIFFERENTIAL DECOMPOSITION IN TERRESTRIAL, FRESHWATER, AND SALTWATER ENVIRONMENTS: A PILOTSTUDY.
al. (12), have typically been used for PMI determinations and are
determined by taking the sum of the average daily temperatures
(°C) for however long the corpse has been decomposing. For example,
one subject may require 4 days (assuming an average daily
temperature of 25°C) to attain an ADD score of 100, while another
subject, decomposing under cooler temperatures, may also obtain
an ADD score of 100, but which would require 20 days (assuming
a daily average temperature of 5°C) to attain the same decompositional
status and hence the same ratios of biomarkers in specific tissues.
This study indicates that ADDs are no longer sufficient to accurately
describe the narrowing PMIs. A more accurate technique,
based on ADDs, is the use of cumulative degree hours (CDHs).
This uses a twelve hour temperature cycle to describe the decompositional
process. Instead of using daily average temperatures, the
average temperature (°C) for each twelve hour interval is cumulatively
added to attain the CDH. For example, if maximum temperature
(30°C) is reached at noon every day and minimum temperature
(10°C) is reached every day at midnight, then in a 24 h period
(one day) the CDH would be 40 CDHs (30 + 10)/2 = 20 for the
first 12 h -- noon to midnight and (10 + 30)/2 = 20 from midnight
to noon for the second twelve h interval resulting in 20 + 20 = 40
I think these are the major works regarding decomposition, especially in salt water.