The key idea here is the hands-on collection of tangible evidence. In this phase, investigators don’t just observe; they record what they see and physically gather items that could prove what happened. This means taking thorough documentation—photographs, notes, and sketches—to capture the scene as it exists, then carefully collecting objects with proper packaging, labeling, and handling to prevent contamination. Preserving the integrity of each item through chain of custody is essential so the evidence remains admissible for analysis in the lab. This focus on recording and retrieving physical items distinguishes it from initial scene work like surveying the area to plan searches, or steps that open or close access to the scene. It’s the dedicated collection effort that turns observed traces into evidence that can be examined microscopically, chemically, or statistically later on.

Bloodstain Pattern Analysis focuses on reconstructing what happened during a bloodshed event by examining how and why the bloodstains were created. It uses details like stain size, shape, distribution, and the geometry of spatter to test hypotheses about the sequence and mechanisms of the violence. The goal is to determine which events could have produced the observed patterns and which could not, such as whether blood was projected directly from a wound, struck by a weapon, or transferred secondarily, and to estimate angles and velocities involved. This approach emphasizes evaluating feasible scenarios given the physical evidence, rather than identifying who committed the act or pinpointing a location in isolation. While BPA can inform considerations about the involved weapon or setting when supported by the patterns, its primary aim is clarifying the events of SAMPLEthe bloodshed itself.

Major case prints provide the known reference material for comparing friction ridge details with latent prints collected at a scene. By capturing rolled impressions of all ten fingers (and often palms), they give a complete, high-quality record that investigators use in the comparison step of the analysis process to determine whether a latent print matches a specific individual. The strength here is that the detailed ridge minutiae available on these prints allow for accurate, conclusive identifications (or exclusions) when compared against all latent prints obtained during the investigation. While these prints do record extensive ridge skin, the key purpose is to enable reliable comparisons, not merely to record prints, train, or be unused.

In sketching, the viewpoint determines how the space and relationships between objects are read. The typical choice is an overhead, top-down perspective, like a bird’s-eye view. This angle lets you see the layout clearly: where things are in relation to one another, how much space there is between items, and how the scene is organized overall. It minimizes distortion from perspective so multiple elements can be shown in one view, which is ideal for conveying placement and spatial relationships quickly. Other angles—looking from below, from the side, or straight on—are useful for focusing on a single object or its details, but they don’t convey the overall layout as effectively. That’s why the bird’s-eye view is described as the common sketch viewpoint.