What method is used to collect hair samples at a crime scene?

The use of tweezers or forceps is an effective method for collecting hair samples at a crime scene because it allows for precise handling and minimizes the risk of contamination. This approach is particularly important in forensic science, where maintaining the integrity of physical evidence is paramount. Tweezers or forceps enable the collector to grasp hair samples without directly touching them, thus avoiding the transfer of additional materials or substances from the collector's hands to the evidence. This method also helps ensure that the hair samples can be preserved in their original state, which is crucial for subsequent analysis and comparisons.

While other methods, such as using sticky tape or a vacuum sweeper, can also be employed in certain contexts for collecting different types of evidence, they may not provide the same level of control or preservation as tweezers or forceps. Using bare hands would likely compromise the quality of the evidence and is typically discouraged. Therefore, the precision and careful handling provided by tweezers or forceps make this method the most appropriate choice for collecting hair samples.