What procedure can an investigator use when a witness may recognize a perpetrator but doesn't know their identity?

The correct procedure for a situation where a witness may recognize a perpetrator but does not know their identity is a lineup. In a lineup, several individuals who resemble the suspect are presented to the witness simultaneously. This method allows the witness to make a choice based on their recognition of the perpetrator while minimizing the risk of misidentification. It is crucial for ensuring that the identification process is fair and that any potential bias is reduced.

The lineup technique provides the witness with an opportunity to see the suspect in a controlled setting among individuals that share similar characteristics, which can enhance the likelihood of a correct identification. It also follows legal protocols, ensuring that the investigative process is reliable and just.

This approach is particularly effective because it engages the witness’s memory in a more direct way compared to other methods, such as a photo array where the witness may only view images. Additionally, it creates a structured environment for identification, which can be more reliable than recalling details from a statement review or relying on a sketch, which may lack the necessary quantum of clarity or resemblance needed for a confident identification.