According to ( http://www.forensicsciencesimplified.org/blood/principles.html) gunshot spatter, includes spatter from the entrance wound as well as, the exit wound. The size, shape, and amount of spatter is varied based upon the caliber of the gun in question, as well as, the distance and angle the victim was struck.
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Cast-off spatter results from when an object such as a bat or something similar, is swung through the air and is thrown off or cast-off of it onto the walls or floor. analysts can usually tell which direction the object was swung by judging the impact and spatter pattern of the cast-off. They can also count the approximate number of strikes or blows by judging the arc and height of the spatter pattern according to ( http://www.forensicsciencesimplified.org/blood/principles.html )
Arterial spray, is the spurt of blood released from the body once a major artery is cut or severed. The blood is released from the cut or severed blood vessel by the pumping of the heart. With every heartbeat, it releases more and more blood. This is why victims expire so quickly once an artery is severed, your heart literally pumps the blood out of your body. This also form and arcing pattern containing large, individual stains. A new pattern is created every time the heart pumps according to ( http://www.forensicsciencesimplified.org/blood/principles.html ).
Expirated spatter is usually caused or created by blood from an internal wound. It mixes with air from the lungs being exhaled from the nose, mouth or an injury to the lungs or airway. This type of spatter tends to usually be a fine or thin mist caused by the pressure caused by the lungs moving air out of the body. Small air bubbles are usually found in the drops of blood according to (http://www.forensicsciencesimplified.org/blood/principles.html ).
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This type of blood spatter is used by hunters such myself to track wounded animals. The air in the blood tells us the animal is hit in the lungs and will most likely, be not much further up the blood trail. Once the blood starts to show air bubbles, death is not far from the animal. This type of blood spatter is a good sign the animal is hit well and will not suffer very much when it is dying from the shot we took.
Some blood stains cannot be seen with our normals eyes. These types of stains are called latent stains. These stains must be seen by using a special chemical call Luminol, this chemical allows us to see blood stains and blood spatter which has been wiped clean or soaked up. Luminol, creates a bright blue glow when it detects and reacts with blood, it reacts with the iron in the blood’s hemoglobin according to ( http://www.forensicsciencesimplified.org/blood/principles.html )
There are several different types of injuries which can be inflicted during a crime. Such as, sharp force injury, this type of injury is usually brought on by a stabbing. They are caused by an object with a small surface area, such as knife or some type of pick. Less blood is brought out on the weapon, resulting in smaller pattern stains. Blunt force injuries however, are created by a weapon such as a bat or hammer. With its larger surface area, the objects produces varying size droplets. The third and final injury, is gunshot injury. This type of spatter is a mist-like spatter
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caused by the bullet entering and exiting the body of the deceased according to ( http://www.forensicsciencesimplified.org/blood/principles.html ).
According to ( http://www.forensicsciencesimplified.org/blood/principles.html) gunshot spatter, includes spatter from the entrance wound as well as, the exit wound. The size, shape, and amount of spatter is varied based upon the caliber of the gun in question, as well as, the distance and angle the victim was struck.
When working as a CSI or just inside a crime scene in general, safety of yourself and others should be your number one concern. It is vital to yourself and those around you or your team, to wear safety equipment and take precautions. CSI personnel should always wear protective equipment such as, gloves and safety glasses. Failure to do so, may result in the contraction of a pathogen such as AIDS, Hepatitis B,C, meningitis or TB. CSI should always wear disposable gloves, masks, and gowns when working a crime scene and must wash hands with antiseptic hand rinse before returning to headquarters or the lab. These above listed items should be disposed of in a recommended biohazard bag upon completion of their purpose. Failure to do so may result in cross-contamination or the contraction of one of the blood pathogens listed above according to ( http://www.practicalhomicide.com/Research/LOmar2007-2.htm ).
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Another type of blood spatter according to ( Crime Scene Forensics, LLC. http://www.crimescene-forensics.com/Crime_Scene_Forensics/Bloodstains.html (2015)) is low force impact spatter. Which is, blood that falls at the speed of gravity. Usually from an open wound or from a surface higher up saturated in or with blood. They usually have a impact diameter of 4mm or more. According to ( http://www.practicalhomicide.com/Research/LOmar2007-2.htm ) the gravitational force exerted on the blood droplet is roughly five feet per second.
Medium-velocity spatter, according to ( http://science.howstuffworks.com/bloodstain-pattern-analysis2.htm) is one whose force is ranged from 5 to 100 feet per second, and has a diameter of no more than 4mm. It can result from a stabbing or being struck with a baseball bat or, an intense and heavy handed strike. According to ( http://www.practicalhomicide.com/Research/LOmar2007-2.htm ) this impact spatter is caused when the victim is struck with a force from five to twenty-five feet per second. The stain resulting from this type of impact spatter, usually is from one to four millimeters in diameter.
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A high-velocity impact spatter, results from and is created by,when the victim is struck with a force greater than one hundred feet per second. The stain which results from such a fast and high impact, is usually less than one millimeter in diameter. Although it is smaller than the rest, this type of stain is associated with and tied into gunshot wounds and/or injuries according to ( http://www.practicalhomicide.com/Research/LOmar2007-2.htm )
Passive stains, are created by an action rather than a directed force. These actions are things such as blood droplets, blood pools, blood clots, drip trails, and drip patterns. also, dynamic stains are created by a force. Example of these are arterial patterns, splash
es, cast-off patterns, and spatter. Spatter patterns, occur when a blood mass is broken up and distributed. The droplets are thrown from their original origin ( the body ) and put onto the surrounding surfaces and scene. Blood spatter can occur on essentially anything, ranging from carpet, wood, tile, wallpaper or clothing. The type of surface the blood droplets strikes, effects how it will spatter and pattern according to ( http://www.practicalhomicide.com/Research/LOmar2007-2.htm ).
Blood spatter, is not strictly used for determining the type of weapon used in a murder or a similar attack. It is also used to either convict or to rule out a person of interest or suspect in a certain case. According to ( http://www.cnn.com/2005/LAW/03/03/johnson/index.html?eref=sitesearch) blood spatter evidence proved Sarah Johnson did not murder her parents. According to Michael Howard of the crime lab which was used as part of the defense team,
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stated whoever shot Diane and Alan Johnson, would have been covered in blood. However, upon inspection of Sarah Johnson’s clothing she was wearing when police arrived, they detected no blood spatter evidence and ruled her out as the gunman, or gunwoman in this case.
It is also very important officers and other CSI’s are trained properly in the handling of blood spatter evidence. Such was not the case known as the Chamberlain Case. According to ( http://science.howstuffworks.com/bloodstain-pattern-analysis5.htm) in August of 1980, the Chamberlin family were camping in the Australian Outback with their two children, a four year old and a ten week old, both girls. Lindy Chamberlin put both girls to bed in their small tent they were camping in. For some unknown reason, she left them and came back a little while later, upon her return, she discovered a small pool of blood and a bloody blanket and cried the Dingo had taken her baby. Other campers and her husband searched for the baby girl, but found nothing more than bloody baby clothing.
Police officers took the bloody blanket and the bloody clothing found at the scene. All of the bloody clothing was found near the entrance to a Dingo lair. The police folded the clothing and when the media arrived, stated it had been found like this. The police in this cases, did an absolute terrible job at preserving blood spatter evidence found in the tent, on the blanket, and on the clothing.
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Lindy and her husband, spent three years in prison because police did not comprehend and try to preserve evidence which clearly supported the child was eaten alive by a Dingo according to ( http://science.howstuffworks.com/bloodstain-pattern-analysis5.htm ).
Blood spatter analysis has caught fire with the public as well as with Hollywood. Television has taken a liking to the show “Dexter”. (http://www.imdb.com/title/tt0773262/plotsummary) A television show where a serial killer does this work as a job for Miami Metro Police. He is a serial killer who works in a police station, how ironic. He uses the evidence of blood spatter to determine and figure out exactly who killed the victim. When he figures it out, he hunts them and kills them violently in return. Since he is a serial killer, he has a trophy system as well as his victims did. He cuts their cheek and collects blood for a blood slide and saves it long side his other trophies. Television shows such as this one, execrates a bit much, but is no way less entertaining.
The use of blood spatter analysis in determining who the murderer is, one of the most crucial and vital aspects of a crime scene. Had this type of analysis not been invented, determining who committed the violent act of murder, would be very difficult and time consuming. Since the invention of blood spatter analysis, the ability to determine the type of weapon used, the angle the weapon was swung, whether the body was struck post-mordum or not has been made easier by the invention and usage of blood spatter analysis.