Which of the following is an internal packaging example for evidence?

The correct choice, a screw top vial, is an example of internal packaging for evidence because it is specifically designed to securely contain smaller items, such as biological samples or substances, that might be collected during an investigation. This type of packaging helps to prevent contamination, spillage, or degradation of the evidence, ensuring its integrity for further analysis.

Screw top vials provide a high degree of sealing, which is especially important for evidence that needs to be preserved in a controlled state. By using this kind of packaging, investigators can maintain the chain of custody and ensure that the evidence remains admissible in court.

The other options, while usable for packaging evidence, do not serve the same purpose as an internal packaging method. For instance, a paper envelope or a cardboard box may be used for larger items or documents but do not offer the specialized protection and containment that a screw top vial provides. Heat sealed plastic bags might also be used for evidence, particularly for items that need to be kept dry or free from air, but they do not have the robustness or security of a screw top vial for containing liquids or volatile substances.