Cordage Analysis
Contributed by Karen Lowe
A cordage examination begins after all other trace evidence has been collected and the remainder of forensic examinations have been conducted on the cordage. First, an overall assessment of the color and construction (e.g. twisted, braided) of the cordage is conducted, and characteristics such as crowns per inch, number of plies, direction of twist (“S” or “Z”) and diameter are examined .
Pieces of cordage are then examined to determine if ends of cordage from different locations/people can by physically fit together. This may be possible with plastic-like cordage or cordage with a paper or fabric core or tracer. If the cordage has a paper or fabric core or tracer, the core is opened to examine the edges/contours of the paper or fabric. If the edges/contours of the paper or fabric physically fit together, it can be concluded that they were once one piece of cordage.
If a physical fit is not possible, the color, construction and composition of the cordage are examined and compared. The examination of the color involves the macroscopic color of the items being compared as well as the microscopic color of the fibers comprising the cordage, which is examined as part of the fiber examination. If the macroscopic color and the construction is the same, a textile fiber examination is conducted on the fibers comprising the piece(s) of cordage to determine composition.
If the color, construction and composition are consistent between pieces of cordage being examined, it can be concluded that they are consistent with originating from the same source, or another source with the same color, construction and composition.
Additional References:
1. ASTM Standard E2225-10, “Standard Guide for Forensic Examination of Fabrics and Cordage,” ASTM International, West Conshohocken, PA, 2010, www.astm.org
2. Wiggins, K., Recognition, Identification and Comparison of Rope and Twine, Science and Justice, 1995, 35(1), pp. 53-58.