Daily Trivia Women blink nearly twice as much as men.

Agenda DT Agenda Bloodstain Notes Classwork Homework

Forensic Science

BPA Bloodstain Pattern Analysis How can an investigator use bloodstain patterns to analyze a crime scene? Location and description of individual stains and patterns Direction a blood droplet was traveling by calculating angles of impact Area of origin of blood source or sources The type of object used in attack (edged, blunt, firearm, etc.) Minimum number of blows The positions of the victim, suspect, and objects during events The sequence of events

Bloodstain Pattern Analysis Terms Spatter – Bloodstains created from the application of force to the area where the blood originated. Origin/Source – The place from where the blood spatter came from. Angle of Impact – The angle at which a blood droplet strikes a surface. Parent Drop – The droplet from which a satellite spatter originates. Satellite Spatters – Small drops of blood that break off from the parent spatter when the blood droplet hits a surface. Spines – The pointed edges of a stain that radiate out from the spatter; can help determine the direction from which the blood traveled.

Passive Bloodstains – Patterns created from the force of gravity – Drop, series of drops, flow patterns, blood pools, etc.

Single Trail Multiple Trail

Pool

Projected Bloodstains –Patterns that occur when a force is applied to the source of the blood –Low, medium, or high impact spatters, cast-off, arterial spurting, expiratory blood blown out of the nose, mouth, or wound.

Arterial Spurt

Radial

Cast off

High vs Low velocity

Transfer or Contact Bloodstains –The pattern created when a wet, bloody object comes in contact with a target surface; may be used to identify an object or body part. –Wipe pattern from an object moving through a bloodstain or swipe pattern from an object leaving a bloodstain.

Luminol Used to locate traces of blood, even if it has been cleaned or removed. Only lasts 30 seconds. Also reacts to some metals, paints, cleaning products and plant matter. Can destroy other evidence in the crime scene. For this reason, investigators only use luminol after exploring a lot of other options

Homework Bloodstain Pattern WS