What is the proper term for a small envelope used to collect hair samples?

The term "bindle" refers specifically to a small envelope or packet designed to collect and preserve evidence, such as hair samples. This term is widely used in forensic science and criminal investigations to ensure that delicate items are properly contained and secured for analysis. A bindle is often made of paper or lightweight materials that minimize contamination and protect the integrity of the evidence.

In contrast, while the other terms may relate to evidence collection in broader contexts, they do not specifically denote the method of packaging small samples like hair. An evidence envelope typically refers to a broader category of containers used for various types of evidence, and a specimen bag is more often used for larger samples or liquid evidence. A sample pouch is not a standardized term in forensic practice. Therefore, "bindle" is the most precise and appropriate term for the context of collecting hair samples.