In the Latent Print Unit (LPU) at the FBI Laboratory in Quantico, Virginia, there is a small, specialized group of qualified forensic examiners and photographers who make up part of the Hazardous Evidence Analysis Team (HEAT). Members of this team undergo rigorous training at partner agency facilities across the nation to gain access to a category of unique evidence: items contaminated with chemical, biological, radiological, nuclear, or explosive materials (CBRNE).

Given the specialized nature of these materials, the standard approach that the LPU would take to examine evidence for the presence of latent prints needed an adjustment. As such, LPU HEAT examiners began adapting their processes and procedures for each unique scenario. One latent print processing technique that the team has taken a creative approach with is known as cyanoacrylate, or superglue, fuming.

Superglue Fuming Basics

One of the workhorses of latent print processing, cyanoacrylate fuming, encapsulates an evidentiary item in a closed chamber and introduces superglue vapors over time to coat the latent prints.

Because of the lack of relative humidity in many locations geographically, humidity is often introduced to enhance the development and success of the technique. This is done to regenerate, or rehydrate, the moisture component of any latent print residue that may be present on the item.

After the item is humidified, liquid superglue is quickly heated until it turns into a gas, which produces vapors that adhere to the regenerated latent residue. Last, the toxic fumes must be purged from the chamber safely.

This entire process results in a plasticized latent print (figure 1) that aids in forensic evidence preservation and print visualization for photographic capture. At this point, that photograph can be digitally transmitted to the FBI Laboratory, where an examiner awaits to analyze and hopefully compare the latent print to any known subjects or search it against the millions of known fingerprint and palm print records maintained in the FBI's database.

While all of this is accomplished daily for run-of-the-mill evidence using automatic and premanufactured chambers in a controlled laboratory setting at Quantico, the HEAT cases face a different set of challenges. For hazardous situations, the LPU HEAT examiners designed a solution to conduct superglue fuming effectively in a variety of environments.

Creative and Simple Path Forward

Examiners created a specialized portable cyanoacrylate fuming kit designed to deploy easily to any location requiring a HEAT response (figure 2). The kit comprises materials that consider many common CBRNE safety issues and allow for chamber versatility to accommodate evidence items of different sizes.

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Related Content

• Cyanoacrylate Fuming — A Mainstay of Crime Scene Investigation, by Don Penven
• Developing Methods to Improve the Quality and Efficiency of Latent Fingermark Development by Superglue Fuming, by Mark D. Dadmun, Ph.D.