Bloodstain Pattern Analysis Trigonometry

Physical evidence left behind at a crime scene plays a crucial role in reconstructing the events that took place involving the crime. Bloodstain pattern analysis (BPA) is a discipline which utilizes the sciences of biology, physics, and mathematics. Bloodstain interpretation may be accomplished by direct scene evaluation and/or careful study of scene photographs in conjunction with detailed examination of clothing, weapons, and other objects regarded as physical evidence. The location, spreading, and appearance of bloodstains and spatters can be useful for interpreting and reconstructing the events that produced the bleeding. An investigator or bloodstain pattern analyst can decipher from individual bloodstains the direction and angle

The world of Forensic Scientist is an amazing and fascinating place. There are so many aspects that go into forensic science but in this paper we are only covering bloodstain spatter patterns. Bloodstain spatter patterns are not solely used to solve crimes but I do feel it is one of the most important. Bloodstains never lie.

It is flung off the weapon or tool during and after the act as a result of centrifugal force. Cast-off spatter is often elliptical in shape which is why it is easily confused with arterial spurting (Sutton, 1998). However, it can also resemble a typical medium velocity droplet any time the blood hits a surface. For example, a blow to the top of the head with an over head strike or simply cast off forming from blood dripping off a weapon after use will result in a similar pattern to a medium or low velocity droplet. Smooth metallic weaponry used will generate a more profound pattern than a textured weapon. In other words an aluminum baseball bat will yield a greater amount of cast off blood than a wooden baseball bat.

The goal of this experiment is to determine the blood types of the samples given and to learn what interactions occurred to each blood type. Determining an individual’s blood type and how it reacts with Anti A, Anti-B, and Anti Rh serums played a crucial part in this experiment. The researcher concluded that agglutination (clumping) occurred in some of the blood samples. For example, Mr. Smith’s blood reacted with Anti-A and Anti-Rh serums (antibodies) allowing the researcher to determine the blood type is A. Mr. Jones’s blood reacted with Anti-B serum but it did not react to Anti-A or Anti Rh allowing the researcher to believe that the blood type is B. Mr. Green’s blood reacted with all serums and caused a reaction to occur resulting the blood type to be AB positive. Mr. Green’s blood also had a positive marker for Rh factor. However, Ms. Brown’s blood had no reaction at all and the researcher determined if no reaction occurred then the sample had no antigens but proved to have some antibodies, resulting in blood type to be O. The purpose of this experiment is to determine whose blood has type A, B, AB, or O.

The body had blood and throw up around her head, she was wearing warmer clothes but it was 73 degrees Fahrenheit in her home. There were two fingerprints on the orange juice glass. The fingerprints both were double loops, the same as Alex Garcia’s. Comparing the fingerprints from the crime scene and Alex Garcia’s, it was noted that both fingerprints had the same ridge patterns and minutiae.

Blood spatter analysts are a crucial part of a homicide investigation. They examine the blood stains left behind at a crime scene with the help of criminal investigators. They try to find a pattern or trail with the blood to figure out what happened at the crime scene. These blood patterns can show where the victim was hit, how they were hit, if they struggled, and what kind of weapon the killer used. They use many techniques to collect evidence that can be analyzed at the lab. Common techniques are measuring the diameter of the blood drop, measuring the spatter zone, and taking pictures. Many analysts try to act out the homicide scene to piece together the crime scene and figure out what happened. They also sketch out the scene to go along

he Blood Spatter Analyst (also known as "Bloodstain Pattern Analyst") uses many techniques to collect and analze blood that has been left behind at a crime scene. They uses swabs and ultraviolet light, as well as photgraphy to collect and analyze trace evidence and recreate spatters. After analyzation of the spatter, they can determine what weapon was used, which direction the suspect or victim went, the number of wounds the victim suffered, the trajectry of a projectile, and what occured during a violent crime.

On the other hand blood spatter on a rough surface creates a blood stain with japed edges. Also Blood strains spread more in softer surfaces. Blood usually makes a spherical shape after separating from the blood source, this shape caused by the surface tension of the blood. The blood drop to pull itself in; both horizontally and vertically due to its surface tension, and will maintain its shape until it collides with something. Blood usually will not break unless acted on by a force, and the force has to be great enough to overcome surface tension. When a drop of blood hits the floor at a 90 degree angle the spatter will be round. A low-velocity spatter will be dependent on height, when distance fallen increases the blood spatter will

Bloodstain pattern analysis (BPA), known in the criminal justice field as blood splatter analysis, has been studied since the 1890s. Blood splatter, or bloodstain pattern constructional readings, is a technique that seeks to piece together the incident that caused an individual’s bleeding. Understanding blood splatter on a wall or various surfaces can be instrumental in formulating if a crime was committed and if the blood discovered at the crime scene can be used as evidence. The first documentation of blood splatter research occurred at the Institute for Forensic Medicine in Poland, by Dr. Eduard Piotrowski . During Dr. Piotrowski’s research and documentation period, where he used live bunnies to research blood splatter from head

As I said about there are many forms of blood splatter patterns for example a single blood drop. Depending on the distance the blood drop as fallen from, it can be a little small drop to a more splattered expanded out drop. When a blood drop is affected by something other than force, it can change the characteristics of the blood drop splatter. Blood in flight is caused by a different source than gravity for instance a gun, or a heavy object. When you get shot blood splatters from the exit wound at a fast pace due to the velocity of the bullet. The direction the bullet went in can change the blood splatter characteristics and the distance it was shot at. A blunt heavy item can also cause blood splatter similar to a gun shot.

used method for this is called “tape lifting” blood stains by taking fingerprints tape and

About the exclusion ratio of 5%, how much extent could you be sure that the blood came from the victim?

Forensic science is a key aspect of Criminal Justice that helps rid the streets of lunatics and murderers. One of the most important fields of forensic science is blood spatter analysis. Under the Crime Scene Investigation, analysts gather the information that could eventually lead to a victim’s killer. Basic and complex information can be found when analyzing blood. We can learn what kind of weapon was used, the time of death of a victim and other important facts that can help a case. The pattern that the blood gives off give forensic scientists the tools that they need to help solve cases.

In this day and age law enforcement agencies use many different types of technology in order to help combat and fight crime. Because technology is forever changing this means law enforcement officials need to stay up to date with the latest technology. I wanted to go over technology that is available to police officers, prison guards, and probation officers. One of the many technologies available to police officers are fingerprint technology which provides him the opportunity to successfully lift prints throughout a crime scene. Once these prints are lifted they will go through the proper chain of custody and be processed by the officers local or state lab to see if there is a match. Another form of technology is if blood is found at the crime, any type of blood that is found at the crime scene of course it would be swabbed, for anything that is collected you would also need to

Every time somebody touches something, they leave behind a unique signature that forever links them to that object. This link is their fingerprints, which are unique to every person, for no two people have the same set, not even family members or identical twins. Palms and toes also leave prints behind, but these are far less commonly found during crime scene investigations. Therefore, fingerprints provide an identification process that is applicable to background checks, biometric security, mass disaster identification, and most importantly, crime scene investigations. Fingerprints are so differentiated because they are made up of distinct patterns of ridges and furrows on the fingers. The ridges are the “raised” portions of the prints, and the furrows are the “recessed” portions. This perceived uniqueness has led some people to falsely accept fingerprint analysis as absolute scientific fact. Although overall fingerprints are reliable, there are definitely situations where their accuracy can come into question.