Forensic Sci Med Pathol (2011) 7:53–62 Table 5 Prediction results for Model #1 using stratiﬁed 10-fold cross validation with 100 replications Saw type Predicted from Model #1 Hand saw Jig saw (22%) reciprocating (30%) and hand saw (48%) Hack saw Portable band (39%) hack saw (35%) bow saw (19%) and molding cut-off (7%) Meat saw Meat saw (89%) and jig saw (11%) Bow saw Bow saw (54%) and molding cut-off saw (46%) Molding cut Hack saw (8%) bow saw (52%) molding cut-off saw off (25%) and meat saw (15%) Reciprocating Jig saw (5%) reciprocating saw (60%) hand saw (35%) Skill saw Skill saw (60%) and cut off-saw (40%) Cut-off saw Skill saw (31%) and cut off-saw (69%) Portable band Portable band saw (76%) and hack saw (24%) Jig saw Jig saw (82%) reciprocating saw (12%) hand saw (6%) Table 6 Prediction results for Model #2 using stratiﬁed 10-fold cross validation with 100 replications Saw type Predicted from Model #2 Hand saw Reciprocating (52%) and hand saw (48%) Hack saw Portable band (39%) hack saw (61%) Meat saw Meat saw (100%) Bow saw Bow saw (34%) and molding cut-off saw (47%) meat saw (19%) Molding cut Bow saw (83%) molding cut-off saw (10%) and meat off saw (7%) Reciprocating Reciprocating saw (65%) hand saw (35%) Skill saw Skill saw (100%) Cut-off saw Cut off-saw (100%) Portable band Portable band saw (88%) and hack saw (12%) Jig saw Jig saw (100%) Key Points 1. 2. 3. Postmortem dismemberment cases are sometimes referred to in the media as corpse mutilation, abuse of corpse and criminal dismemberment. The style and design of the teeth, width of the teeth, teeth per inch (tpi), degree of wear on the teeth, saw cutting speed, blade vibration, defects in the blade, and erratic sawing motion are factors that affect the kerf. Accurate microscopic measurements may be more difﬁcult when the kerf shoulders are ﬁbrous. Analyzing kerf mark measurements can be an effective method for predicting and eliminating possible saw blades by comparing the width of the blade to the width of the kerf. 61 4. 5. Statistical model #2 provides more accurate predic- tions of possible saw types based on kerf widths than Model #1. However, both models have limitations; when the categories cannot be separated, there may be higher false probability rates. The boxplot of kerf widths in Fig. 21 provides the investigator with a reference guide for eliminating saw types based on kerf width range calculations. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which per- mits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. References 1. Saul FP, Saul JM, Symes SA. The lady in the box. Proc Am Acad For Sci. 2005;11:300. 2. Saville PA, Hainsworth SV, Rutty GN. Cutting crime: the anal- ysis of the ‘‘uniqueness’’ of saw marks on bone. Int J Legal Med. 2007;121.5:349–57. 3. Bonte W. Tool marks in bones and cartilage. J Forensic Sci. 1975;20:315–23. 4. Rowe WF. Forensic science: an introduction to scientiﬁc and investigative techniques. In: James SH, Nordby JJ, editors. Firearms and toolmarks examinations. Boca Raton, Florida: CRC Press; 2003. p. 327–55. 5. Bertino AJ, Bertino PN. Forensic science: fundamentals and investigations. Mason, Ohio: South-Western Cengage Learning; 2008. p. 470–4. 6. Hueske EE. Firearms and toolmarks. In: Mozayani A, Noziglia C, editors. Forensic laboratory handbook: procedures and practice. Towowa, NJ: Humana Press Inc; 2006. p. 143–5. 7. Nickell J, Fischer JF. Crime science: methods of forensic detection. Lexington: University Press of Kentucky; 1999. p. 154–7. 8. Davis JE. An introduction to tool marks, ﬁrearms and the stria- graph. Springﬁeld: Charles C Thomas; 1958. p. 7–25. 9. Grybowski R, Miller J, Moran B, Murdock J, Nichols R, Thompson R. Firearm/toolmark identiﬁcation: passing the reli- ability test under federal and state evidentiary standards. AFTE J. 2003;35:209–21. 10. Symes SA, Berryman HE, Smith OC. Saw marks in bone: introduction and examination of residual kerf contour. In: Reichs KJ, editor. Forensic osteology: advances in the identiﬁcation of human remains. 2nd ed. Springﬁeld: Charles C Thomas; 1998. p. 393–5. 11. Agresti A. Categorical data analysis. 2nd ed. Hoboken, N.J: Wiley; 2002. p. 165–266. 12. Stokes ME, Davis CS, Koch GG. Categorical data analysis using the SAS system. 2nd ed. Cary, NC: SAS Institute Inc; 2003. p. 181–240. 13. Freas L. Assessment of saw-blade wear patterns and wear-related features of the kerf wall. Proc Am Acad For Sci. 2004;10:303–4. 14. Freas L. Scanning electron microscopy of saw marks in bone: assessment of wear-related features of the kerf wall. Proc Am Acad For Sci. 2006;12:296. 15. Symes SA, Kroman AM, Thurston Myster SM, Rainwater CW, Matia JJ. Anthropological saw mark analysis on bone: what is the potential of dismemberment interpretation? Proc Am Acad For Sci. 2006;12:301. 123