A human body is difficult to dispose of when it is no longer ambulatory. How does one hide a heavy, leaky and fleshy package that, if discovered, could raise serious questions about who, what, why and how the cadaver came to be?
Carmen Montenegro allegedly solved that problem with her deceased ex-boyfriend by sawing him up into pieces and burying his body parts around Ontario, California. She reasoned that the head and arms could be easily identified, so she planted them in potted flowers and gave them to her cousin on Mother’s Day.
Teenagers Daniel Biggs, Sarah Morris and Matthew Welsh had the same problem after they tortured and beat 14 year old Adam Morrell to death in Loughborough, Leicestershire. Once the body was hacked up with a saw and placed in a variety of plastic bags, they found it much more convenient to dispose of the evidence in small parcels.
Forensic investigators were able to put the pieces of the puzzle back together, including linking the tools to the wounds and then to the perpetrators, creating powerful evidence that cut through to the heart of the matter.
Marking it up: from bullets to blades.
Every weapon leaves distinct markings that can help identify the source. Bullets are identified by strata on the sides of the projectile created by distinctions in the gun barrel which discharged it. Saw blades leave distinctive markings on bone and tissue, and although tissue degrades quickly, bone wounds by saw and knife blades can tell a story about the type of blade, how the blade was applied, if the cut was by a power tool or a hand tool, along with many other clues. Investigators, forensic anthropologists and medical examiners can also determine if the cut marks were made post-mortem (after the victim is deceased) or were the cause of death.
Cuts and catalogs: classification and how it works.
Recently, the US Department of Justice conducted a detailed analysis of saw blade indications in human bone and published a report describing the examination of criminal mutilation and dismemberment. The study analyzed hundreds of potential tool marks, cut directions, progressions and bone decay and created a catalog of unique features of saw and serrated knife characteristics, and narrowed the tools to 15 classifications. Each classification creates distinctive marks depending on angle of teeth setting, for example. If the teeth are serrated right and left, they carve out a wider ‘kerf’ or groove, and will penetrate a hard material without binding.
Up close: kerf depth and other distinctions.
Saw mark analysis examines the kerf depth, width and characteristics, as well as the walls of the groove. Since saws separate two parts, grooves on disconnected parts will match, although the saw sides could have distinctive qualities which may leave particular marks. When the blade stops, changes direction or binds, the individual teeth can leave a pattern which can also be ascribed to a particular tool, if the tool is available to be matched.
Other distinctions come from the effect of the blade trauma on the bone. When a terminal cut is completed, a breakaway spur is formed. This is determined by the fracture of the bone as the pressure of the blade is released from the cut. The opposing indication of the breakaway spur is a notch which forms opposite to the spur, and is a complimentary individualistic marker. The size of this spur can help differentiate between the classifications; a handheld circular saw or a chain saw will make a larger breakaway spur than that of a garden hand saw, which by its very nature has less leverage and force.
Directions of motion are also identified and classified. Back and forth motion, angle of application, circular strata on the groove walls, straight or wavy all tell stories about how a victim was mutilated and cut into parts. A cut bone allows the protected bone marrow to be exposed, which hastens degradation and decay. These criteria also provide clues to identifying a limb that may be disassociated with other body parts.
Wounding, weapons and your imagination.
Saws and serrated blades can create deep and ragged wounds on victims. While tools such as these provide a convenient way for a criminal to reduce the mass and weight of a body by separating the parts, saws have also been used to slaughter people in a horrible manner. Chain saw horror movies speak to our most basic fears. The idea of a blade not just cutting, but tearing and slashing, throwing off flesh and blood is not only unnerving, but fascinating in its very revulsion.
The fact that crime scene first responders may see the messy results of a saw blade murder, or that a forensic anthropologist might see the evidence of a saw used on a corpse that was either dead or alive when cut is determined by the markings left behind. It is our imaginations that magnify the terror of mutilation by sharp force trauma.
Your Turn: Do you know of any other cases where dismemberment has been involved? What other types of clues can a corpse give away regarding what has occurred post-mortem? Let us know in the comments — we’d love to hear from you.