Which type of exemplars must never be packaged with questioned samples?

Known exemplars must never be packaged with questioned samples because maintaining the integrity of each sample is critical in forensic analysis. Known exemplars are reference materials that are established as the source of a particular characteristic or trait, such as fingerprints, DNA, or handwriting, and are used to compare against questioned materials collected from a crime scene.

If known exemplars are packaged with questioned samples, it could lead to cross-contamination, which would compromise the validity of the investigation. This contamination can result in misinterpretation of evidence, casting doubt on the conclusions drawn from the analysis. Forensic protocols emphasize that known samples must be kept separate to ensure accurate and reliable results during comparison and analysis, thereby preserving the chain of custody and the integrity of the evidence.

In contrast, unknown exemplars, sample exemplars, and presumptive exemplars have different roles that do not pose the same risks of contamination when handled correctly during investigations.