Bloodstain pattern analysis (BPA) is the interpretation of bloodstains at a crime scene in order to recreate the actions that caused the bloodshed. Analysts examine the size, shape, distribution, and location of the bloodstains to decide what happened. BPA uses biology (behavior of blood), physics (cohesion, surface tension, and velocity) and mathematics (geometry, distance, and angle) to assist investigators in answering questions like:
• From where did the blood originate from?
• What was the cause of the bloodshed? (weapons used)
• From what direction was the victim wounded?
• What were the positions of the victim/ attacker during the bloodshed?
• Did anyone/anything move around after the bloodshed?
• How many possible people were present
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(See figure 5)
In figure WHATEVER, the only force is gravity (Fg.) This force can be described by the equation:
Fg = mg,
Gravity is a descending path. This causes a projectile to move in the downward direction. Since both of them are perpendicular, the force of gravity could never alter the horizontal velocity of an object because they are free of each other. A vertical force does not affect a horizontal motion. The result of vertical force acting upon a horizontally moving object is to cause the object to stray from its otherwise line path. (See Figure 6)
Before, I mentioned that we are assuming there is no air resistance and thus, the only force acting on the blood drop is gravity. However, this is not the case. Air resistance plays a huge role on the path blood drops take. ( See Figure 7) The path it takes will start off parabolic, but will turn linear as it reaches terminal velocity. The drag force (and terminal velocity) differ for different particles in the scene depending on their size and shape. Stokes’ Law applies for spherical objects in a fluid. This law states the drag force
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High velocity blood spatter can be caused by high-speed machines, most commonly caused by guns. (See figure 17)
Types of Stains
Bloodstains are classified into three basic types: passive stains, transfer stains and projected or impact stains. Passive stains include drops, flow and pools, and typically result from gravity acting on an injured body.(See figure 18) Transfer stains result from objects coming into contact with existing bloodstains and leaving wipes, swipes or pattern transfers behind such as a bloody hand print or a smear from a body being dragged.(See Figure 19) Impact stains result from blood jutting out into the air and are usually seen as spatter, but may also include gushes, splashes and spurts. (See figure 20)
Gunshot spatter includes spatter from the exit wound and spatter from the entrance wound. Gunshot spatter will differ depending on the capacity of the gun, where the wound is on the victim, if the bullet exits the body or not, distance between the victim and the gun and location of the victim relative to permanent objects at the crime scene (walls, floors.) (See Figure
In Blood In Blood Out is a drama directed by Taylor Hackford, and starring Damian Chapa (Miklo), Benjamin Bratt (Paco), and Jesse Borrego (Cruz), produced by Hollywood Pictures. The film was based off everyday life in East Los Angeles, from the 1970’s through the 1980’s. Damian Chapa stars as Miklo in the film, a Mexican-American who wanted to be accepted, not by his skin but for the Mexican within him. Benjamin Bratt (Paco) was the older cousin of Miklo, who learned his lesson throughout the movie and changed his ways. Jesse Borrego (Cruz) is the step-brother of Paco who was a talent artist, who ended up turning to drugs because of back problems caused by a rival gang incident.
Each system, as noted early, contributes to reversing cause of shock in this phase. The first of this will be seen when cause of shock is from hemorrhage and significant blood loss from the body, and all components of the hematologic system, or from blood, has its own function as a response (Kolecki “Pathophysiology”). The body’s process of quickly locating and slowing down bleeding within the body is called hemostasis. As soon as a blood vessel is broken, both the liquid and solid components within the blood effect how the body responds (Tortura 703).
As the purple virus enters in Bob's body by using the knee as an entry way, tiny platelets rush to cover the gash and stop the bleeding. In the wet, warm, red bloodstream, red blood cells and white blood cells flow through it. They travel through the stream with the assistance of the heart.
In case if the firearm is involved, we can approach it as both movable and non-movable object. At the initial stage it can be processed with a super glue fuming and later packed into the paper envelope for the further analysis. In case of the blood stains on it we can go back to the initial stage for the swabbing procedure.
Blood is an extremely potent acid, possibly some type of "hydrosulfuric acid" compound, due to its corrosive ability and its effects on living tissue. Can corrode almost any substance. It is dull yellowish-green in color, and appears to be pressurized inside the body so that it spurts out with great force when the creature is wounded. Xenomorph is immune to its own acidic and toxic liquids, similar to how human stomach's are immune to its own digestive fluids. **See information at bottom of post**
It is particularly significant with kids, in addition to with costumes which entitle for blood close to the mouth, for example vampires. In order to formulate artificial blood, combine three portion of corn syrup along with one part of water, and then put in red food color gradually awaiting when you get the shade you wish for. But if you would like a dim, tanned shade to the blood, put in approximately few drops of chocolate syrup. On the way to solidify it, gradually combine in corn starch when it get to the preferred texture. The combination is going to be so gluey at start, however if the superiority assist it in stay then put it on throughout application.
When the blood stops being pumped, gravity makes it settle and it changes the color of the skin where it pools, making it purple-red. This is known as livor mortis or hypostasis. [2]
The force of attraction by which terrestrial bodies tend to fall toward the centre of the earth.
Low-Velocity impact spatters are caused by blood that drops normally or perpendicularly due to gravitational interference and have the largest diameter compared to Medium-Velocity impact spatters. The bloodstains sources are usually open wounds of victims who are sustaining their injuries and surfaces full of blood. Low velocity impact spatters are circular bloodstains with a diameter of not less than 4mm. Increase in distance from the surface, increases the diameter of the blood. However, the increase would remain constant at about 1.2m from the surface. Low-Velocity Impact Spatters were created by drops of blood that travel less than 1.5m/s. Low-Velocity Impact Spatters can be caused by sustaining an injury from blunt objects. Medium-velocity
In order to reconstruct a crime scene, analysis must classify the bloodstain spatter, and there are many way to classify blood stain patterns: bloodstain spatter by velocity and bloodstain through taxonomy. In the classification of the bloodstain spatter by velocity, there are three basic categories of stain groups...
Blood stains are one type of evidence that can be found at a crime scene. Blood that is still in the liquid form should be picked up on a gauze pad. Once the blood is dried thoroughly it should be refrigerated and sent to the Laboratory (Andrus et al., n.d., para. 1). If the blood stain is found dried on clothing, the officer should wrap the piece of clothing in clean paper and place it in a sealed and labeled container. An object with dried blood stains needs to be sent to the Laboratory if it is small enough. If the object is too large to send, then using a clean knife the stain needs to be scraped onto a clean piece of paper, which then can be folded and placed in an envelope (Andrus et al., n.d., para. 2). When collecting autopsy blood samples, the officer should request that the pathologist obtain the sample directly from the heart and place it in a yellow or purple stoppered vacutainer. If the victim is still alive but in serious need of a blood transfusion, then the pre-transfusion blood sample needs to be obtained promptly before the hospital discards it (Andrus et al., n.d., para. 4). It is important for the Laboratory to receive all blood samples within 48 ho...
Blunt force trauma is defined as a traumatic event caused by the introduction of any blunt instrument forcefully, causing injury to the body or head. The Severity of injury is determined by various factors. It may be due to mechanical force such as compression, traction, torsion or shear. Impact of the injury and severity depends on object and movement of victim. Injuries occurred may be internal such as lacerations of internal tissues, organs, fractures of bones or may be external such as abrasion, avulsion, contusion and laceration (Pollak & Saukko, 2009). Severity also depends on anatomical site impacted for ex: Lacerations have irregular margin, hanging causes abrasions, contusions and hyoid bone fractures, Ocular hemorrhages in case of blunt trauma to eyes or Fracture of ribs when hit on chest by a blunt object (Ressel, Hetzel, & Ricci, 2016). Severity is also determined by the duration of time and amount of force applied. Nature of trauma is of importance in forensic medicine. It helps in
As the player is jumping, his torso is moving upward with some velocity. The velocity increases as he straightens his legs in order for him to jump higher. As a result, his center of mass is accelerating upward, indicating that he is experiencing a net force upwards, allowing him to elevate because the normal force is greater than the gravitations force.
Much like in Toms case, most investigations start with a crime having been committed. Forensic ballistics and firearm investigation start when there are bullets, cartridges, a weapon, or any combination of the above found at a crime scene. With the evidence, a crime lab can search for clues on these items that could lead to a suspect or possibly prove that the items were used in the crime. By comparing the markings on bullets or cartridges found at the scene with those fired from a suspect’s weapon, a ballistics expert can often determine if the rounds came from the same weapon. Just the act of cycling a cartridge through a weapon without firing it can leave permanent scratches in the case that are unique to the weapon.