By C. K. Hull & Associates
[Cindy Hull, Juan Rodriguez and Paul Catena]
The first thing you learn in evidence handling is to protect and secure your evidence. One thing that is overlooked through the whole process is the evidence tape your agency is using. Is it really tamper proof?
There are so many different kinds of evidence tape for sale, tamper resistant; security tape; super stick; pre-cut; sawtooth; transparent; color coded, E-Z peel; integrity strips; seal guard; split back; super seal and heavy gauge to name a few. Which evidence tape is best for your agency, for which type of evidence packaging (paper bag or plastic) and the environment where your evidence is stored (freezer, room temperature, refrigerator, warehouse)?
To answer the question, C. K. Hull & Associates performed a study to test and compare various types of evidence tape on their durability and the strength of their adhesive after being exposed to different environmental elements in a three-month
span.
The evidence tape used in testing were acetate based, styrene plastic based and paper based. The evidence tapes were used on paper and plastic evidence bags in three different types of environmental conditions:
- freezer
- outside exposed to heat (approximately 80-102 degrees), direct sunlight, cold mornings, and some moisture
- room temperature
The Seal Guard, from Arrowhead Forensics, and Tri-Tech Forensics evidence tape used during testing are an acetate product and the evidence tape used from CSI Forensic Supply is a styrene plastic based product. Both type of evidence tape, acetate and styrene plastic based products, broke apart at room temperature which can easily detect if the evidence package had been tampered with. The Super Seal evidence tape proved to have the strongest adhesive and did not fall apart at room temperature.
The outdoor and freezer environments produced the same results on both paper and plastic evidence bags:
- Arrowhead Forensics Seal Guard (acetate based): Strong adhesive, tears easily, evident if tampered with
- Arrowhead Forensics Super Seal (paper based): Strongest adhesive, difficult to tear, evident if tampered with
- Tri-Tech Forensics (acetate based): Strong adhesive, reasonable force needed to tear, evident if tampered with
- CSI Forensic Supply (styrene plastic): Weak adhesive, tears easily, evident if tampered with
- Scotch packaging tape: Very difficult to tear, possible to lift and replace, not tamper evident
The Arrowhead Forensics Super Seal tape has shown to have the strongest seal and most tamper resistant material. The adhesive strength of the acetate based evidence tape and styrene plastic evidence tapes were not as strong as the Super Seal. However, the acetate based evidence tapes did work well at room temperature. The Scotch packaging tape is very strong and can be used as a base tape to seal evidence packages as long as you apply evidence tape over the Scotch packing tape.
So, when packaging your evidence, keep in mind the type of environment your evidence will be in and ask yourself, will the evidence tape still be on the package when I retrieve for court?