IAI Crime Scene Analyst Practice Test 2025 - Free Crime Scene Analysis Practice Questions and Study Guide

The type of marks formed when an instrument is pushed or forced into a material are referred to as compression marks. These marks occur as a result of the force exerted on the surface, causing it to deform under the pressure of the object. Compression marks are commonly found on softer materials, such as soft soils, polymers, or various types of textiles, where the instrument compresses the material, leading to a defining imprint that can provide valuable information about the object that made the mark.

Impression marks typically result from an object resting on a softer surface without significant force, creating a shape but not penetrating into the material. Scraping marks involve a motion where an object slides along a surface, removing or displacing material rather than compressing or indenting it. Indentation marks can resemble compression marks, but they more specifically refer to an imprint left by an object that digs or presses into a surface without necessarily applying a consistent force that deforms the outline, whereas compression implies a broader area of material being pressed down. Thus, compression marks are the most accurate description of the marks left by an instrument forcefully pressed into a material.