In what type of packaging should bloody evidence be placed?

When collecting and preserving bloody evidence, it is essential to use materials that allow for proper ventilation while also protecting the integrity of the sample. Paper bags are the correct choice because they are breathable. This prevents the moisture from the blood, which can lead to the growth of mold and bacteria, thus compromising the evidence.

Moreover, paper bags help in avoiding contamination which could happen if the evidence is stored in airtight containers. Plastic bags, for example, can trap moisture and promote degradation over time. Glass containers, while protective, are not ideal for biological evidence because they do not allow for airflow, and the risks of breakage during transport or handling can lead to loss of critical evidence. Sealed envelopes, similar to plastic bags, do not provide the necessary breathability needed for biological samples. Therefore, utilizing paper bags offers the best balance between protection and preservation for bloody evidence.