Blood Spatter Analysis

Blood Sample Collection Methods Swab – Use a web swab to transfer the blood onto the swab (must allow it to dry!) Scrape – Use a file and tweezers to scrape and lift off the blood sample Cut out – Take the entire piece with you

Blood Spatter Analysis Passive Transfer Projected

Transfer Occurs when wet bloody surface comes in contact with another surface, leaving a trace or impression of blood A recognizable image may or may not appear

Passive Drops as an action of gravity Can be categorized into drops, clots, pools, drip patterns

Projected Blood spatter can occur on all types of surfaces but may appear slightly different Glass (very smooth) Linoleum (slight texture) Wood/concrete (very textured

Projected Projected blood spatter occurs when the initial source is exposed to an action or a force Size, shape, and number of stains will depend on the amount of force used sin(impact angle) = width/length

Blood Spatter

Impact Speed Low Impact High Impact Medium Impact

Shape of Spatter - Direction WHY?

Point of Convergence The blood spatter can be retraced to a single area – giving investigators clues to how the crime occurred