ASIS International (ASIS) Professional Certified Investigator Practice Exam

Which method is specifically used for raising fingerprints from fabric or paper?

1. Ninhydrin

2. Cyanoacrylate fuming

3. Iodine fuming

4. Powder dusting

The correct answer is: Iodine fuming

Ninhydrin is the method specifically used for raising fingerprints from fabric or paper. This chemical reacts with amino acids present in the fingerprint residue, producing a visible purple or blue stain. This reaction is particularly effective on porous surfaces like fabric and paper, where fingerprints may be absorbed, making them difficult to detect with other methods. Iodine fuming, while applicable to some surfaces, is primarily used for developing latent prints on non-porous surfaces, and the prints it reveals are often temporary, requiring immediate photography or fixing. Cyanoacrylate fuming is generally more effective on non-porous surfaces as well, working by creating a hard, white polymer over the fingerprint. Powder dusting is suitable for non-porous surfaces and does not work well on materials such as fabric or paper, as the powders may not adhere properly. Each of these methods has its specific use case, but Ninhydrin stands out for porous materials like fabric and paper.