Forensic toolmark examiners compare marks between those observed on an item/surface and those made by a reference implement, such as a particular tool or weapon, to provide an opinion of the likelihood of common origin. It is widely accepted that such comparison opinions need to be underpinned by empirical research, and this study aimed to add to the knowledge base relied upon when developing and comparing saw marks in bone, a substrate encountered in body dismemberment cases. Porcine bones were used as a human proxy; they were either fresh with residual soft tissue and bodily fluids present (\'wet\') to replicate dismembered bones shortly post-mortem, or processed to remove soft tissue and moisture content (\'dry\') to represent cases of dismemberment after an extended period of decomposition and exposure. The bones were cut using one implement of each of five classes: hand saw, mitre saw, reciprocating saw, oscillating saw, and serrated knife. They were cut, either completely through (except for serrated knife), giving two surfaces per cut to examine, or to a depth up to 3 mm (false starts). Five replicates per combination of bone condition, saw, and cut type gave 130 bone samples. These were then cleaned and cast using Isomark Silicone Polymer Compound or Mikrosil, giving 260 cast samples. All bone and cast samples were photographed, examined for various class characteristic markers, and specific markers measured. No significant differences between Isomark and Mikrosil casts were observed when compared side-by-side, demonstrating suitability of both materials for casting of saw marks on bone. Although saw marks presented more class characteristic markers on dry than wet bones, calculations of tooth distances and measurements of kerf width (KW) from marks did not significantly differ between bone conditions, with exception of the reciprocating saw that produced false start marks with significantly larger minimum KW on wet than dry samples. Further analysis supported that tooth distances on marks made by hand and oscillating saws are sufficiently accurate for the determination of saw teeth per inch (TPI). However, one tooth distance on marks made by reciprocating saws did not accurately represent TPI. Finally, examination of presence or absence of class characteristic markers on each saw mark demonstrated consistent variation between saw classes. These results enabled the development of exclusion-based decision trees, and a reference database (available on request), for use by toolmark examiners in their evaluation of saw types based on class characteristic markers observed in cut bone.

A review of New York City dismemberment cases occurring between 1996 and 2017 was conducted, which resulted in a total of 55 dismembered decedents in a 22-year period. Annual trends indicate an average of 2.5 dismembered decedents. Additional results show that 53% of cases involved transection only, 35% involved disarticulation only, and 13% involved a combination of both. When the entire body could be accounted for, the average number of body portions per case was 5.5. Frequent locations for dismemberment were the neck, shoulders, hips, and knees. Dismemberment locations showed a general trend of anatomical symmetry. Seventy-eight percent of the dismemberments involve disposal of body parts in an outside location. Eighty-four percent were concealed from view with some type of covering. The findings from New York City are compared with other studies.

In this experiment, 170 experimental false starts on human (120 lesions) and pig bones (50 lesions) were analyzed under stereomicroscope. The goal was to evaluate the potential of three \"secondary\" features (patterns of striae on the kerf floor, blade drift and bone islands) to diagnose saw class and saw set. We also assessed the performance of each of these features in ambiguous cases observed in a previous study, based on three main characters (minimum width of the kerf, shape of the kerf walls, and shape of the kerf profile). Among these three \"secondary\" features, striae on the kerf floor proved to be useful: the undulating or undulating/straight pattern of the striae on the kerf floor indicates an alternating set whereas thin and straight striae indicates a wavy set. Blade drift and bone islands may be indicative of large teeth size. These secondary features, in combination with the three main characters previously studied, may help identify the class of the saw.

This experimental study examined false starts because these are seldom discussed in the forensic literature and usually concern animal bones rather than human bones. We created 170 experimental false starts (50 on pig femurs and 120 on human femurs) using five different saws (4 with an alternating set of teeth, and one with a wavy set). Teeth per inch (TPI) ranged from 7 to 24. Saws were classified as either rip saws or universal saws. The bone lesions were studied using stereomicroscopy. This study focused on three features that are easily observed with a stereomicroscope: the minimum width of the kerf, the profile of the lesions (concave or convex), and the shape of the edges (narrow-wide pattern, necking in the middle, or straight pattern). These features proved to be useful clues to recognize the class of the saw. Our study found some variability between lesions but also some repetitive features that allow for the classification the handsaws studied according to class. There were also some significant differences in lesions between pig bones and human bones, suggesting that pig femurs (versus human femurs) are not always a good alternative for studying saw marks.

Mutilation is a rare and unusual act performed on a victim, especially in cases of homicide. Knowledge on mutilation homicide is scarce as the base rate of this type of homicide is very low. Moreover, previous studies examining this specific criminal behavior have been mainly descriptive, neglecting to look at other factors related to the act of mutilation. Furthermore, depending on the cultural context and country of origin, the infliction of mutilation pre-, per-, or post-homicide translates into different meanings. Therefore, it is important to examine mutilation homicide in the context of non-Western countries. Using crime and forensic examination reports subjected to forensic examination and convicted for a homicide between 1995 and 2011 (N = 1,200) in Korea, the rate of mutilation homicide was estimated. Based on the 65 cases (5.4%) identified, information on the offenses and offenders were described. Moreover, using a series of bivariate analyses, the current study compared cases of mutilation homicides in Korea with other countries. Findings revealed interesting differences and similarities between mutilation homicide cases from Korea and the other countries. For instance, offender-victim relationship, victim\'s gender, and criminal history were significantly different from the comparison groups. In addition, compared with Korea, mutilation homicide cases were significantly more likely to involve an accomplice in Finland, suggesting the need to carry the body over a long distance. Investigators and researchers need to understand the cultural context in which these acts are committed as the infliction of mutilation may serve different purposes across different countries.