Fire Scene Evidence Collection Guide

Fabric & Fibers

Ropes and Cordage

Detailed Procedure:

Ropes and cordage can be made of various materials: natural fibers (eg: jute); synthetic fibers (eg: nylon); or of a combination of materials (eg: fabric core with a woven sheath around it). There are many aspects of ropes and cordage to examine, including plies, fiber content, and construction. The knots associated with the cordage may also be examined and offer some evidential information if the knot is unusual.

To collect ropes and cordage:

  1. Photograph the item in place.

  2. Wear new, unused, clean latex or nitrile gloves.

  3. If there are multiple items, package each item separately as described below. Change gloves between items.

  4. If the cordage is tied to a person or object, it may be necessary to cut it. Carefully mark either side of where you will make the cut with tape, string, or other method. If multiple cuts are required, differentiate between the cut locations with different colors of tape, string, or other system. Then, cut cleanly between the marked points, preserving the knotted portion. Do not untie any knots.

  5. If the cordage will be examined for only DNA or trace, an air-tight container is not necessary. Wet cordage should be dried by hanging it over clean paper or drying it on clean paper. When the cordage is dry, it should then be rolled in the paper it was dried over (to preserve any trace evidence that fell onto to the paper) and then sealed in a paper bag or box (packaging that is not air-tight) with identifying information, including case number, date, exhibit number, a brief description, and your name.

  6. If the cordage will be analyzed for ignitable liquids, label a new metal paint can or nylon fire debris bag large enough for the item with identifying information, including case number, date, exhibit number, a brief description, and your name. Recover the cordage by carefully lifting it and placing it in the container. Do not dry the cordage prior to packaging. Leave 1/3 headspace in the container.

  7. There may be situations where drying the wet cordage will compromise evidence. For example, if you would need DNA analysis done on a piece of evidence (which requires breathable packaging) and fire debris analysis (which requires air-tight packaging), the lab may tell you to package the wet cordage in an air-tight container and bring it to the lab immediately so that the fire debris analysts can collect their evidence before the item is taken out of the air-tight container and dried for subsequent DNA analysis. Be sure to check with the laboratory when multiple analyses are desired on items of evidence.

  8. Place the cordage in the appropriate container as described above and seal the container.

  9. Store the item in a secure location, such as a locked evidence van or your vehicle, until you are able to transport it to the laboratory. Please note that special storage may be required if the rope or cordage may bear biological evidence, which should not be left in a hot car. Consult your laboratory for assistance.

  10. Work with the laboratory to determine the sequence of examination if you are requesting more than one kind of testing.

Laboratory testing of ropes and cordage:

The rope and/or cordage can be compared to a known sample by analyzing the construction, fiber type, and possibly end-use, if the cordage is unusual. A physical match between questioned and known samples may be achieved in some cases. Also, examination of the type of knot may be useful in some instances. DNA and trace evidence may be adhering to the rope or cordage.