Which of the following is considered a known sample?

A known sample is a biological specimen that can be definitively linked to a specific individual. In the context of forensic analysis, buccal swabs collected from a suspect provide DNA that is distinct and identifiable to that person. This type of sample can be compared directly against evidence collected from a crime scene or from other biological samples.

The importance of known samples lies in their capability to establish a definitive connection to a suspect, as they are obtained directly from a source where the identity is known. Buccal swabs include cells from the inside of the cheek, which contain DNA material that can be analyzed for comparison purposes in forensic investigations.

In contrast, hair collected from the crime scene does not guarantee a match back to a specific individual without additional context or analysis. A random sample of DNA from the population cannot be linked to a specific case or individual, and a witness's verbal statement is not a biological sample and does not provide a genetic profile.