Citrate Content of Bone as a Measure of Postmortem Interval: An External Validation Study

Abstract

The postmortem interval (PMI) of skeletal remains is a crucial piece of information that can help establish the time dimension in criminal cases. Unfortunately, the accurate and reliable determination of PMI from bone continues to evade forensic investigators despite concerted efforts over the past decades to develop suitable qualitative and quantitative methods. A relatively new PMI method based on the analysis of citrate content of bone was developed by Schwarcz et al. The main objective of our research was to determine whether this work could be externally validated. Thirty-one bone samples were obtained from the Forensic Anthropology Center, University of Tennessee, Knoxville, and the Onondaga County Medical Examiner's Office. Results from analyzing samples with PMI greater than 2 years suggest that the hypothetical relationship between the citrate content of bone and PMI is much weaker than reported. It was also observed that the average absolute error between the PMI value estimated using the equation proposed by Schwarcz et al. and the actual ("true") PMI of the sample was negative indicating an underestimation in PMI. These findings are identical to those reported by Kanz et al. Despite these results this method may still serve as a technique to sort ancient from more recent skeletal cases, after further, similar validation studies have been conducted.

Human Bone Proteomes before and after Decomposition: Investigating the Effects of Biological Variation and Taphonomic Alteration on Bone Protein Profiles and the Implications for Forensic Proteomics

“…PMI estimation often relies on visual assessment of gross morphological changes of the body during decomposition, − even though the rate of these changes is known to be highly variable. , Accuracy of the PMI estimation decreases as decomposition progresses, and interobserver reliability differs depending on the method and the experience of the researcher. , Biochemical techniques have shown promising results in the search for a precise and accurate method to estimate late PMI in human bone; however, these methods are yet to be validated for use in forensic contexts. − …”

Estimation of Late Postmortem Interval: Where Do We Stand? A Literature Review

“…Kanz et al [ 33 ] observed that the degradation rate of citrate seemed to be slower in soil-buried bones compared to those deposited on the surface. Brown et al [ 34 ] did not find significant correlation between citrate content and PMI, although they did observe a decrease in citrate content with increasing PMI.…”

“…[ 31 ]. The use of citrate content in bone as a predictor of PMI has shown mixed results in various studies [ 31 , 32 , 33 , 34 ]. While certain studies have demonstrated a correlation between citrate content and PMI, other studies have not reached statistically significant results.…”