An analysis of more than 100 cases involving knots and ligatures: knot frequencies, consistent tying habits and noteworthy outliers

Abstract

Knot data from 114 cases were tabulated. Some of the evidence had been lost, or was of such low quality that no knot identification or analysis could be made, thus highlighting the need for careful preservation at the scene. Only 3–6% of exhibit tiers produced sophisticated knots, and these individuals were consistent in the chirality of such formations as Bowlines and Sheet Bends. Most tiers produced simple, basic Half Knots, Half Hitches, Granny Knots, Reef Knots, Overhand Loops and Slip Loops. Tiers demonstrated repeatable tying patterns, weakly or strongly favouring one chiral enantiomer over the other. The S enantiomer occurred more frequently in the case evidence presented. Some tiers reversed the chirality of an initial or terminal knot in an otherwise consistent string of Half Hitches or Half Knots. Contextual clues provided by the types of knots – in addition to their capsizement, location and function – indicated whether one or two wends were employed in the tying. Ubiquitous tying materials were noted. These included items of utility and availability found at the scene, such as clothing and cable as well as rope and cord. The reported observations support previous research and can guide future analyses of knotted evidence.

Keywords:

• forensic sciences
• behavioural sciences
• knots and ligatures
• knot chirality
• tying habits

Notes

^*Although some journals eschew capitalized knot titles, capitals are usually applied to knots named after people and places. An effort has been made to standardize this, and subsequently avoid confusion, by capitalizing all specific knots names 3 ^, 4 ^, 7 ^, 8.

^†Physicists Dorian M. Raymer and Douglas E. Smith15 reported research pertaining to the spontaneous knotting of string, which was performed at the University of California at San Diego. String was tumbled inside a box, and it was found that complex knots often formed in seconds. In topological terms, almost all of the knots were prime knots, being unlinked and indecomposable16 ^, 17. Tumbling generated 120 different types of knots having minimum crossing numbers up to 11.