Liquid blood evidence is generally collected from blood pools but can be collected off of clothing as well, using a gauze pad or a sterile cotton cloth. Once the sample is collected it must be refrigerated or frozen and brought to the laboratory as quickly as possible.
How is blood evidence transferred?
Blood evidence isn’t just collected off of weapons, but can also be collected off of the floor or other surfaces in a crime scene. … – Transfer Stains/Patterns -A transfer bloodstain pattern is created when a wet, bloody surface contacts a surface that is not bloody.
What is a transfer blood pattern?
A transfer pattern is a pattern that forms when a wet, bloody surface comes in contact with a second surface. A recognizable image of all or part of the object that caused the pattern can sometimes be observed in the pattern.
What type of weapon causes a transfer of blood?
High velocity blood spatter is usually caused by a gunshot, it can also be caused by other objects too if enough force is exerted. The force of the blood hitting a surface for high velocity blood spatter is over 100 feet per second.
What can the presence of blood at a crime scene reveal to investigators?
This understanding is important, because the interpretation of blood spatter patterns and other evidence at crime scenes may reveal important investigative information, such as the positions of the victim, assailant, and objects at the scene; the type of weapon that was used to cause the spatter; the number of blows, …
What are the three types of blood evidence?
Bloodstains are classified into three basic types: passive stains, transfer stains and projected or impact stains.
What types of evidence can be transferred?
Transfer evidence is defined as any evidential substance or particle such as blood , fluids , hairs, fibers , paint, and skin that is exchanged between an assailant and the victim or the scene of the crime. Such evidence can transfer either from the criminal to the victim or from the victim to the criminal.
What are the two types of transfer blood patterns?
Swipe Pattern — the transfer of blood onto a surface not already contaminated with blood. One side is usually feathered which indicates the direction of travel. Wipe Pattern — created when an object moves through blood that has not completely dried and moves, removes, or otherwise alters it.
What are the 4 types of passive bloodstains?
Passive bloodstains can be further subdivided to include drops, drip patterns, pools, and clots.
- Passive Bloodstain. Passive Bloodstain on a rough surface (such as wood or concrete) …
- Projected Bloodstain. Projected Bloodstain, possibly a Cast-Off Pattern or a HVIS. …
- Transfer Bloodstain.
What is a wipe pattern?
A wipe pattern is “An altered bloodstain pattern resulting from an object moving through a pre-existing wet bloodstain.”
What is a wipe bloodstain pattern?
Wipe Pattern – An altered bloodstain pattern resulting from an object moving through a preexisting wet bloodstain.
What is the stringing method?
The string method is one of the oldest techniques for determining an space in which the bloodletting occurred, based on a bloodstain pattern. First, angle of impact and area of convergence needs to be determined. … Now, the string will show a general origin of the bloodletting.
What is the difference between blood spatter and blood transfer?
surface. SPATTER VS TRANSFER: The simplest type of blood spatter analysis is determining spatters from transfers. … Transfers occur when a blood source comes in direct contact with a target surface area.
What are two examples of tests that can be done to detect blood at a crime scene?
What are two examples of tests that can be done to detect blood at a crime scene? The presence of blood can be detected through luminescence (Luminol test), by the Kastle-Meyer test using phenolphthalein and hydrogen peroxide.
What are the most important aspects of finding blood at a crime scene?
Generally, blood evidence is usually more informative in cases where a suspect and victim are in contact or close proximity. For example, if a suspect stabs or beats a victim, there could be an exchange of blood between the victim and the suspect. If a suspect shoots a victim from across a room.
What four properties of a crime scene can be identified from blood spatter?
What can you learn from blood spatter? You can learn the origin of stain, direction of impact, speed, position of victim and assailant, number of blows, shots.