Question

1. use the fingerprint below to complete the following. (bertino & bertino, pg. 162 - 165)

a. identify the type of print below:
b. locate the core, delta, and at least 3 different types of minutiae. ridge count each to the core.

1. describe the procedure for creating a cast of a plastic impression. distinguish between the casting materials and process you would choose for a shoeprint in soil, a shoeprint in snow, or a tool mark impression.
2. what is the importance of exemplars?
3. what are the limitations of impression evidence, such as collecting, analyzing, and probative value?

what limitations are associated with each aspect of impression evidence?
collecting
analyzing
probative value

Explanation:

a. This fingerprint appears to be a whorl type as it has a circular - like pattern with ridges forming concentric circles or spirals.
b. The core is the approximate center of the fingerprint pattern. The delta is a triangular - like area where the ridges diverge. Minutiae include ridge endings (where a ridge stops), bifurcations (where a ridge splits into two), and dots (small, isolated ridges). To ridge - count to the core, one would start from a minutia point and count the number of ridges between it and the core.
For question 9, to create a cast of a plastic impression, first, clean the area around the impression to remove debris. Then, mix the casting material (such as dental stone or plaster of Paris) according to the manufacturer's instructions. Pour the mixed material slowly into the impression, ensuring it fills all details. Let it set and harden. For a shoeprint in soil, a fast - setting material like dental stone can be used. For a shoeprint in snow, a material that can harden in cold conditions and not melt the snow, like a special cold - resistant casting compound, is needed. For a tool mark impression, a more rigid casting material might be preferred to capture fine details.
For question 10, exemplars are important as they are known samples used for comparison. They help in determining if a particular impression or mark came from a specific source, such as a suspect's shoe or tool.
For question 11, in collecting impression evidence, limitations include the potential for damage to the impression during collection, difficulty in finding and preserving impressions in some environments (e.g., soft or wet soil). In analyzing, limitations are that impressions may be partial or distorted, making accurate identification challenging. In terms of probative value, there can be issues with uniqueness and the possibility of similar impressions from different sources, which can affect its use as conclusive evidence in court.

Answer:

a. Whorl
b. Core: Center of pattern; Delta: Triangular area; Minutiae: Ridge endings, bifurcations, dots; Ridge - count: Count ridges between minutia and core

1. Casting plastic impression: Clean area, mix casting material, pour, let set. Soil shoeprint: Dental stone; Snow shoeprint: Cold - resistant compound; Tool mark: Rigid material
2. Known samples for comparison to determine source
3. Collecting: Potential damage, environmental difficulties; Analyzing: Partial/distorted impressions; Probative Value: Uniqueness and similar - source issues