When packaging a knife with a visible fingerprint in blood, how should it be secured?

When securing a knife that has a visible fingerprint in blood, using a box and ensuring it doesn’t move is the appropriate method. This approach is optimal for several reasons.

First, utilizing a box provides a rigid structure that protects the knife and the evidence from contamination, physical damage, or environmental factors that may degrade the quality of the fingerprint. A stable container minimizes the risk of movement, which is crucial because even slight shifts can smudge or alter the latent print.

Moreover, the box can be sealed to maintain the integrity of the evidence, ensuring that it remains in a controlled environment until it is analyzed. This method also aids in chain of custody, as it is easier to label and document the evidence securely within a box than in other types of packaging.

In contrast, the other methods listed may not provide the same level of protection or control. For instance, placing it in a paper bag can allow for movement, which could jeopardize the fingerprint's integrity. Wrapping it in plastic wrap may trap moisture, which can damage both the fingerprint and the knife itself. Storing it loose in a tray offers no protection and leaves the evidence vulnerable to contamination or loss.

In summary, using a box that secures the knife ensures that the evidence remains