blood spatter analysis

The examination of the shapes, locations and distribution patterns of bloodstains in order to provide an interpretation of the physical events by which they were created that is based on the premise that all bloodstains and bloodstain patterns are characteristic of the forces that have created them.The examination of the shapes, locations and distribution patterns of bloodstains in order to provide an interpretation of the physical events by which they were created that is based on the premise that all bloodstains and bloodstain patterns are characteristic of the forces that have created them.

The interpritation of blood stains found at the scene of a crime or on effects such as clothing can be used to:

Confirm or prove theorys to be fulse on the events and there sequence at a crime:

Theses includes position of victim (laying, standing, sitting)

Evidence of movement (blood smears, flow patterns, drip trails)

They are also used to prove or disprove fundamental aspects of a case:

Such as wether or not the blood stains on a suspects clothing matches there report of the crime.

Or are the stain patters on the victim and or the crime scene consistant with the accounts given by the witnesses, victim or the suspect.

Blood properties:

Blood volume on average makes up 8% of overall body weight.

4 to 5 litres of blood for women

5 to 6 litres of blood for men

A 40% blood volume loss both internally and or externally causes irreversable shock (death)

A blood loss of 1.5 litres of blood both internally and or externally causes incapcitation.

blood surface texture:

Blood stains can occour on almost every surface wood, tiles, carpet, clothing....ect

Depending on what surface blood droplets.

The surface blood droplets strike has a large effect on the stain disorbtion and satellite (secondary) blood spatter.

Blood droplets that strike hard smooth surfaces such as glass will have next to no distrotian on there peripheral edges.

Blood droplets that strike linoleum flooring will take on a slightly different appearance and my tend to have scalloping on there peripheral edges.

Blood droplets that strike surfaces such as wood or concrete will have a much larger effect on the shape of the blood stain sometimes creating secondary or satellite blood spatter and stains.

general categorisation of blood stains:

Drip stains/ patterns

gravity only

Transfer stains/ patterns

a blood contaminated object(s) contacting a surface

Misting stains/ patterns

this occurs when a fourse strikes the body stronger than the force of gravity

Transfer blood stains:

A transfer blood stain occurs when a wet blooded surface comes into contact with another object.

A recognisable image of all or a portion of the original surface may be observed in the pattern.

Blood drop elongation:

the way in which blood drop elongation works is that the longer the droplet the lower the angle in which it struck the surface

conclusion:

To conclude there is lots you can learn form the possition and shape of blood spatter and stains at a crime scene and it is vital to the integrity and exactitude of a case.

#productivity #timemanagement