Anatulie Marais-Werner

Bio: Anatulie Marais-Werner is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 2 citations.

Decomposition patterns of buried remains in the Central Highveld region of South Africa

Abstract: Understanding the process of decomposition is extremely important and aids in criminal investigations, especially when attempting to estimate the post mortem interval (PMI). Although several studies have been conducted on the decomposition patterns in surface remains, much less is known about this process in buried remains. By quantifying decomposition rates, factors influencing decomposition and research on the process of decomposition can be standardised and validated in a South African setting. The aim of this study was to record decomposition stages and rates of buried remains and to compare it to that of remains decomposing on the surface. Twenty five pigs (Sus scrofa; 4580 kg) were buried and excavated at different post mortem intervals [7 days (1 week), 14 days (2 weeks), 33 days (1 month), 92 days (3 months) and 183 days (6 months)]. Stages of decomposition were scored according to separate categories for different anatomical regions based on standardised methods, and photographed. The point values for each region were added to determine the total body score (TBS), which represents the stage of decomposition for each pig. When studying decomposition, accumulated degree days (ADD) are effective in standardising the effect of variables (i.e., temperature) that influence the decay process. It also enables researchers to replicate experiments and compare results. In this study, ADD were used to measure the rate of decomposition and to compare decomposition rates between buried and surface remains. Results indicated that early stages of decomposition occured rapidly for both surface and buried remains within 7-33 days. Differences in the degree of decay were especially noticeable with the buried, 7 day interval pigs that displayed variations in discolouration in the lower abdomen and trunk. Between 14 and 33 days, buried pigs displayed common features associated with the early stages of decomposition, such as discolouration and bloating. The pigs then reached a stage of advanced decay where little change was observed in the next ±90-183 days after internment. Similar patterns of decomposition were observed for surface remains with rapid decay during the early stages of decay where after a plateau phase was reached during advanced decay. However, as expected, the surface remains reached higher TBS scores during similar intervals. iii In this study, the decomposition rates of buried remains were mostly influenced by being buried at an average depth of 0.75 m which could have resulted in lower in-soil temperatures and limited insect activity at a depth of 0.75 m on the remains. Also, adipocere presented itself on the remains with the 33 day PMI pigs, the 92 day PMI pigs and 183 day PMI pigs. Adipocere is capable of degrading over a prolonged period which reduces the rate of decay in a conducive environment (i.e., burial in soil). Overall, surface and buried pigs decompose with similar patterns, but buried pigs decompose at a much slower rate, reaching lower TBS values relative to similar PMIs in surface remains. This suggests that burial does have a significant effect on the rate of decomposition. Results from this study suggest that when using TBS guidelines on buried remains in the Central Highveld region of South Africa, buried remains will have, on average, a lower TBS score (7.4) than surface remains within a similar post mortem interval.

The development of a post-mortem interval estimation for human remains found on land in the Netherlands

Abstract: The decomposition process of human remains can be used to estimate the post-mortem interval (PMI), but decomposition varies due to many factors. Temperature is believed to be the most important and can be connected to decomposition by using the accumulated degree days (ADD). The aim of this research was to develop a decomposition scoring method and to develop a formula to estimate the PMI by using the developed decomposition scoring method and ADD. A decomposition scoring method and a Book of Reference (visual resource) were made. Ninety-one cases were used to develop a method to estimate the PMI. The photographs were scored using the decomposition scoring method. The temperature data was provided by the Royal Netherlands Meteorological Institute. The PMI was estimated using the total decomposition score (TDS) and using the TDS and ADD. The latter required an additional step, namely to calculate the ADD from the finding date back until the predicted day of death. The developed decomposition scoring method had a high interrater reliability. The TDS significantly estimates the PMI (R 2 = 0.67 and 0.80 for indoor and outdoor bodies, respectively). When using the ADD, the R 2 decreased to 0.66 and 0.56. The developed decomposition scoring method is a practical method to measure decomposition for human remains found on land. The PMI can be estimated using this method, but caution is advised in cases with a long PMI. The ADD does not account for all the heat present in a decomposing remain and is therefore a possible bias.

A comparison between decomposition rates of buried and surface remains in a temperate region of South Africa.

Abstract: Several studies have been conducted on decomposition patterns and rates of surface remains; however, much less are known about this process for buried remains. Understanding the process of decomposition in buried remains is extremely important and aids in criminal investigations, especially when attempting to estimate the post mortem interval (PMI). The aim of this study was to compare the rates of decomposition between buried and surface remains. For this purpose, 25 pigs (Sus scrofa; 45-80 kg) were buried and excavated at different post mortem intervals (7, 14, 33, 92, and 183 days). The observed total body scores were then compared to those of surface remains decomposing at the same location. Stages of decomposition were scored according to separate categories for different anatomical regions based on standardised methods. Variation in the degree of decomposition was considerable especially with the buried 7-day interval pigs that displayed different degrees of discolouration in the lower abdomen and trunk. At 14 and 33 days, buried pigs displayed features commonly associated with the early stages of decomposition, but with less variation. A state of advanced decomposition was reached where little change was observed in the next ±90-183 days after interment. Although the patterns of decomposition for buried and surface remains were very similar, the rates differed considerably. Based on the observations made in this study, guidelines for the estimation of PMI are proposed. This pertains to buried remains found at a depth of approximately 0.75 m in the Central Highveld of South Africa.