Forensic Bloodstain Analysis

Blood is the most commonly encountered body fluid in criminal casework, shed in a wide range of circumstances. It can be deposited onto surfaces, including the scene of an incident and the clothing and footwear of any people who may be present. Blood may also be found on weapons and other items that may have been nearby or which bloodstained individuals have come into contact with.

During an assault, blood is often transferred from the victim to the assailant. If only a single blow is struck, detectable quantities of blood may not be picked up by the assailant as he may have moved on before the bleeding starts. However, if the assailant makes significant contact with the victim after the onset of bleeding he may well become heavily bloodstained. If several blows are struck, blood may spatter. When blows into wet blood are struck, people in close proximity to the incident may become splashed or smeared with another’s blood even though they had not been responsible for the particular injuries form which the blood came.

Considerations can include impact spatter which may occur when a hard object impacts into a wet bloodstained surface, causing blood to spatter away from the impact site. The stains typically appear as small spots and splashes wherever they land. Impact spatter may be caused if a blow is delivered to wet blood on a person’s skin or clothing. It is typically found in cases involving kicking, punching or beating with a blunt instrument.

Also, contact stains which occur when an object that is wet with blood comes into contact with an unstained surface, or when an existing blood stain that is still wet is smeared by contact with another surface.

Such stains and patterns can be interpreted by Bericon's Blood Spatter Experts and may provide investigators with useful information concerning the events which have taken place. This information can then be used when evaluating any statements provided by complainants, defendants and other witnesses. It is important to appreciate that just because someone may have an injured person's blood on them; this does not necessarily mean that they had been involved in any criminal activity.