In the first experiment, the investigators were given four dyes, each representing a blood sample. One of which was present at the crime scene while the other three samples belonged to the three different suspects. An electrophoresis buffer (Tris-Borate-EDTA) was used in this experiment by having the running buffer placed in the electrophoresis chamber. After an agarose gel with four wells was added facing the negative end of the chamber, the investigators used micropipettes to transfer 10 µl of a sample into a well. Once the samples were loaded, negative and positive plugs were inserted into their respective inputs and the power source was turned on at 100 volts. After 22 minutes, the dyes moved from the negatively-situated wells to the positively-situated
The affects of pH, temperature, and salt concentration on the enzyme lactase were all expected to have an effect on enzymatic activity, compared to an untreated 25oC control. The reactions incubated at 37oC were hypothesized to increase the enzymatic activity, because it is normal human body temperature. This hypothesis was supported by the results. The reaction incubated to 60oC was expected to decrease the enzymatic activity, because it is much higher than normal body temperature, however this hypothesis was not supported. When incubated to 0oC, the reaction rate was hypothesized to decrease, and according to the results the hypothesis was supported. Both in low and high pH, the reaction rate was hypothesized to decrease, which was also supported by the results. Lastly, the reaction rate was hypothesized to decrease in a higher salt concentration, which was also supported by the results.
The DNA retrieved from the reaction can then be. imported into an apparatus using gel electrophoresis to compare the sample of DNA to other. samples. The. In our experiment we learned the how to replicate tiny samples of DNA into usable amounts and how to analyze the specimen using gel electrophoresis.
Investigators can find clues from a murder through a number of different ways. Typically they find out how many times someone has been stabbed or however many blows they received. Through the count of the times the action had been performed they can come to an understanding of whatever hand the suspect was using. Other information can tell how the suspect was standing over their victim during the time of death. A common tool that forensic units use is the ultra violet or UV light. An ultra violet light can detect different areas that contain blood that might not be able to be seen in other conditions. Another common tool is the blood reagent test that forensics use on scene. These tests determine if the blood is human or animal. (Renee Blake)
The analysis of the samples should be used only to confirm or negate match between the sample taken from the crime scene fgand the sample taken from the suspect. That is, it should sdfremain as an identifgication tool only. There should be no further analysis of the DNA to suggest psychological characteristics that would make the suspect more likely to have cdfommitted the crime. This rule should apply also to samples taken from convicted dfdoffenders for a data vor dagta bank.
The blood of the unknown person became apparent through comparing the blood type found at the crime scene with the contrasting blood types of the suspects. The blood identified at the crime scene could have possibly belonged to Anna Garcia or Erica Piedmont. This observation was based on the information that the blood type found at the crime scene was type A and these two individuals are the only ones that carry that specific type. In similarity, a microscopic photography was taken of the unknown hair follicle found at the crime scene. Then hair samples were taken from the potential suspects, and the victim. These findings were then compared. This was done by looking at each individuals hair follicles and comparing it with the unknown one. By looking at the similarities and differences in medulla diameter, the discovery of the unknown hair follicle became established that it belonged to Anna Garcia. Further examination resulted in the analyzation of a shoe print found at the crime scene. Shoe patterns and sizes were taken from each suspect, including the victims. They were then identified and compared to the one found at the crime scene. By looking at the distinct pattern, size, and the fact that both shoes were a Columbia brand sneaker it became obvious that the shoe print was extremely similar to Anna’s shoe design. Through this found evidence it became
On Wednesday, November 16, 2011, Katherine Stang, Aresh Kabirnavaei, and Andrew Roller, all students in the Master’s of Forensic Science program gave thesis presentations to the Forensic Seminar Class. The following paragraphs will summarize each topic.
The criminal justice system has changed a lot since the good old days of the Wild West when pretty much anything was legal. Criminals were dealt with in any fashion the law enforcement saw fit. The science of catching criminals has evolved since these days. We are better at catching criminals than ever and we owe this advancement to forensic science. The development of forensic science has given us the important techniques of fingerprinting and DNA analysis. We can use these techniques to catch criminals, prove people's innocence, and keep track of inmates after they have been paroled. There are many different ways of solving crimes using forensic evidence. One of these ways is using blood spatter analysis; this is where the distribution and pattern of bloodstains is studied to find the nature of the event that caused the blood spatter. Many things go into the determination of the cause including: the effects of various types of physical forces on blood, the interaction between blood and the surfaces on which it falls, the location of the person shedding the blood, the location and actions of the assailant, and the movement of them both during the incident. Another common type of forensic evidence is trace evidence. This is commonly recovered from any number of items at a crime scene. These items can include carpet fibers, clothing fibers, or hair found in or around the crime scene. Hairs recovered from crime scenes can be used as an important source of DNA. Examination of material recovered from a victim's or suspect's clothing can allow association to be made between the victim and other people, places, or things involved in the investigation. DNA analysis is the most important part of forensic science. DNA evidence can come in many forms at the crime scene. Some of these forms include hair; bodily fluids recovered at the crime scene or on the victim's body, skin under the victim's fingernails, blood, and many others. This DNA can be the basis of someone's guilt or innocence; it has decided many cases in the twentieth century. As the times continue to change and the criminals get smarter we will always need to find new ways to catch them. Forensic science is the most advanced method yet, but is only the beginning. As the field of science grows so will the abilities of the
...me scene, by recreating the scene using the blood direction a bloodstain patterns. Bloodstain pattern analysis use biology, chemistry, math, and physics to solve a crime. In doing research on this topic there is a lot of detail to go into this topic, so in suggestion this paper need to explain the other different investigators that process any crime scene.
A crime scene investigator is the individual who arrives at a crime scene and not only searches and preserves evidence located on the crime scene, but also sends off evidence that may assist in determining the identity of victims and murders to the appropriate personnel. This individual implements several of methods in order to gather the appropriate evidence. Some of the ways that they gather the evidence is by lifting fingerprints, gathering blood, gathering saliva, gathering any hand written documents, taking photos of tattoos, gathering teeth, gathering hair and so much more. These individuals truly play a huge role in the discovery of the individual’s identity. Although crime scene investigators carry an important role in gathering data it is also important to look at what methods are used and how they can lead to the discovery of a deceased individual’s
In light of police procedure of handling and examining evidence before DNA analysis, it is speculated that this contamination could be due to environmental DNA via multiple transfers from gloves to exhibits. In contrast, domestic contamination could arise from inadequate protective equipment such as infrequently changed gloves or even indirect transfer from the outside of evidence bags (rare at 0.0024% vs contamination by police at 0.04%). New profiling systems may have increased the detection rate of contamination events, and police protocols fall short of matching the new standards required. Even though police contamination events increased, NIPH contamination has been on the decline with the main risk coming from before the bag even sets an anthropomorphized foot in the
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...
In here I will clarify each potential evidences of the crime and explain of the application of the identified forensic procedure to the facts of the case. One of the perpetrators cuts his hand when trying to drag of the witness in the crime scene. Thus, in this case blood stains would be the one of the potential evidence. The precipitin test might be applied to bloodstains in a numerous ways. It conduct...
Many of us enjoy watching crime scene investigation shows, but in the criminal justice system forensic investigation is an essential field that requires upright observations and a prodigious interpretation. Under forensics, it is difficult to blame someone without scientific data. For that reason, Larry K. Gaines author of the textbook Criminal Justice in Action explains the importance of Blood Spatter Analysis. Specialist can learn a great deal about violent crime by examining where blood landed at the scene, the size and consistency of drops, and the pattern of blood spatter (Gaines, 2011). Consequently, an article of the Blood Spatter Analysis will be used to explain the research methodology the author uses to proceed certain investigations.
As far back as 1832, James Marsh was the first to use forensics at trial to give evidence as a chemist in 1832. Since that time forensic science and evidence has come a long way in various ways and technology to help in determine if the suspect is guilt or not, through such things as DNA testing, blood, and fingerprints. The first forensic police crime lab was created in 1910. The contributions of Dr. Edmond Locard, a French scientist and criminologist, proposed that “everything leaves a trace”. This principle is still valid today as it was so many years ago. No matter how small, the specialized trained technicians and investigators can take these methods and go to a crime scene to get evidence. “Forensic science is the application of sciences such as physics, chemistry, biology, computer science and engineering to matters of law.” (Office of Justice, 2017) These different sciences can help achieve and assist in solving a case. Forensic science has also the ability to prove that a crime was committed, it can find the elements of the crime, it can help place the suspect at the scene and whether the suspect had any contact with the victim. However, in the last several years the techniques and with the use of technology the evidence that forensic science uncovers can also exonerate an innocent individual who has been falsely accused of the
When a suspect’s weapon is examined in the lab, it will be test fired into a box filled with cotton or a tank of water to provide the examiner with the bullets and cartridges with a known history. Using a microscope, the known cartridges are compared with the ones in question. With some patience, skill, and a little luck, experts can definitively say that a certain firearm and no other fired this bullet, or ejected this cartridge.