Abstract:
Forensic anthropologists are tasked with interpreting the sequence of events from death to the discovery
of a body. Burned bone often evokes questions as to the timing of burning events. The purpose of this
study was to assess the progression of thermal damage on bones with advancement in decomposition.
Twenty-five pigs in various stages of decomposition (fresh, early, advanced, early and late
skeletonisation) were exposed to fire for 30 min. The scored heat-related features on bone included
colour change (unaltered, charred, calcined), brown and heat borders, heat lines, delineation, greasy
bone, joint shielding, predictable and minimal cracking, delamination and heat-induced fractures.
Colour changes were scored according to a ranked percentage scale (0–3) and the remaining traits as
absent or present (0/1). Kappa statistics was used to evaluate intra- and inter-observer error. Transition
analysis was used to formulate probability mass functions [P(X = jji)] to predict decomposition stage
from the scored features of thermal destruction. Nine traits displayed potential to predict decomposition
stage from burned remains. An increase in calcined and charred bone occurred synchronously with
advancement of decomposition with subsequent decrease in unaltered surfaces. Greasy bone appeared
more often in the early/fresh stages (fleshed bone). Heat borders, heat lines, delineation, joint shielding,
predictable and minimal cracking are associated with advanced decomposition, when bone remains wet
but lacks extensive soft tissue protection. Brown burn/borders, delamination and other heat-induced
fractures are associated with early and late skeletonisation, showing that organic composition of bone
and percentage of flesh present affect the manner in which it burns. No statistically significant difference
was noted among observers for the majority of the traits, indicating that they can be scored reliably.
Based on the data analysis, the pattern of heat-induced changes may assist in estimating decomposition
stage from unknown, burned remains.
