Blood Evidence Research Paper

In McClure, Weisburd and Wilson (2008) summary article arguing that in addition to bench science, field experimentation involving forensic methods is key to assess the utility of various methods to solve crimes. The study reflected that there is a need for more research into many aspects of forensic science, criticizing the strength of scientific evidence that’s collected at a crime scene and interpretations of most forensic methods while omitting DNA testing. McClure et al’s (2008) explains that in sexual cases and homicides, the presence of DNA evidence actually increased the likelihood of prosecution and a conviction. According to the article “…the case of convictions, the odds-ratio for the presence of DNA evidence was 33.1 for sexual offenses and 23.1 for homicides” (McClure et al., 2008). Subsequently, the research shows that there was a consistent gradual decline in the national homicide rates that began in the 1900s and continued through into the 21st century. The decline of homicides in the US has dropped by from more than 90% in the 1960s to 62% in 2003. Even though this significant drop has occurred during the introduction of the new DNA testing

To make it all worse another women’s body was found in the bay with matching DNA of the killer. A break in the case happened when a victim of a rape came forward. Although, the victim came forward she was having problems discussing the event. O’Tool was able to get the victim to open up during the questioning do obtain vital answers. The victim was attacked in her home when she answered the door. While the man tried to rape her the women’s son came home. The man ran off but the son and the women got a description of the man. The man was described as a black male, handsome, welcoming, and during the attacked told the women he had been watching her. The biggest break in this incident was the DNA matching this person to those of the

suspects in a case, an analyzed DNA sample from the crime scene does not significantly help

Beginning in the mid-1980s, the development of DNA analysis technology has revolutionised the field of forensic science within the criminal justice system. As the refinement of procedures and technology continues, even minute samples of biological material (including blood, saliva, semen and skin cells) are able to be analysed and used to link or acquit perpetrators of crimes. (Whitney, R n.d.)

DNA’s certainty is dramatized in today’s society, which gives lay people the impression that DNA is infallible; however, in the case of Wayne Butler and others, the fallibility of DNA is exposed. Wayne Butler was accused of sadistically murdering Natasha Douty who was found beaten to death on Brampton Island in 1983. Wayne Butler was vacationing on Brampton Island during the timeframe of the murder; however, claimed to be jogging during this time. After submitting a blood test, Butler was eliminated as a suspect. However, Butler was arrested in 2001 for this murder because semen, which was found on the towel at the crime scene, was found to be a match. The John Tonge Centre performed a DNA test on the evidence on the towel. Butler was found innocent after it was identified that the John Tonge Centre mislabeled the test tubes containing the crime scene evidence. (“DNA Evidence”) This case proves that DNA testing may not be as reliable as we think.

DNA forensics can also narrow down suspect pools, exonerate innocent suspects, and link crimes together if the same DNA is found at both scenes. However, without existing suspects, a DNA profile cannot direct an investigation because current knowledge of genotype-phenotype relation is too vague for DNA phenotyping. For example, a profile from a first time offender that has no match in any database may give the information that the criminal is a left handed male of medium stature with red hair and freckles. It would be impossible to interview every man who fits that description. However, with available suspects, DNA forensics has many advantages over other forms of evidence. One is the longevity of DNA. Although it will deteriorate if exposed to sunlight, it can remain intact for centuries under proper conditions (Sachs, 2004). Because DNA is so durable, investigators can reopen old cases to reexamine evidence.

DNA technology has been used as a means to identify perpetrators of rapes and murders with a very high degree of reliability. However, interpretation of the evidence can be problematic at times. This problem comes into play when there are mixed sample’s, partial profiles and with contamination of the evidence submitted. Mixed samples

The first DNA-based conviction in the United States occurred shortly after in 1987 when the Circuit Court in Orange County, Florida, convicted Tommy Lee Andrews of rape after DNA tests matched his DNA from a blood sample with that of semen traces found in a rape victim (Calandro, 2005). It was two years later that DNA was again ruled admissible in a Virginia state ruling. In the years that followed the use of DNA in trial proceeding was not disputed. It was not until the technique of obtaining the evidence was more largely used did the practice become questionable.

There were numerous mistakes made during the investigation of this crime and although Mr. Hunt’s blood type was not a match for the DNA found at the scene of the crime, he was still convicted. While that fact could not be ignored today, it is still possible to prosecute cases like this without conclusive DNA evidence. According to Brand (2006), some jurisdictions do not have the resources to conduct DNA analysis. In addition, today’s jurors expect physical evidence and the absence of it raises reasonable doubt (Brand, 2006). Defendants may still be prosecuted based on other direct and circumstantial evidence such as a witnesses’ personal account.

Since the beginning of DNA testing in 1985, biological material like skin, hair, semen, or blood has been the most unequivocal physical evidence at a crime scene, especially at a sexual assault scene. DNA has a specific, complex, genetic blueprint that distinguishes each person. Forensic testing can determine if distinctive patterns in the genetic material found at a crime scene matches the DNA in a potential perpetrator with better than 99% accuracy. This can be seen in the case of Tommie Lee Andrews who was the first person to be convicted by DNA evidence in 1987. Also in Seattle with the Green River Killer, Gary Ridgway. He was responsible for murders that took place in the 1980s and '90s.

There have been many incidents where cases have needed a solid prosecution in order to convict the defendant in a murder or rape case. This is where DNA Testing comes in to help. By taking a DNA test, a person can be found guilty or not guilty. If a person claims they have been raped there can be a sperm sample taken from the suspect in order to prove that he is guilty or not. In addition, in a murder case there can be blood taken from the suspect so they can tell of his innocence. There are several ways to determine whether a person is guilty or not by this method. Many cases have begun to use this method saying that it is foolproof. People say this is the method of the future of crime

Because there are many different types of crimes, it is often difficult to find enough physical evidence to convict a person. For example, in rape cases there is usually only a small amount of physical evidence, so cases are based on word alone. Because of DNA testing we can now take samples from the victim and attempt to match the results with those of the suspect. Therefore, DNA is sometimes the only real way of determining the guilt or innocence of a suspect without having any witnesses. Since many rape cases are left unsolved, DNA testing is believed to be the most accurate way of keeping sex offenders off the street. Because of the growing trend of using DNA in rape cases especially, a company in Brooklyn now advertises a small flashlight-like device intended to be used to jab at attackers in order to collect a sample of his skin for later use (Adler). According to a study by Joseph Peterson, with the Department of Criminal Justice at the University of Illinois, DNA evidence does not have a major impact on the decision to either convict or acquit

There have been many criminal cases across Australia where DNA evidence has been used to “convict the guilty and clear the innocent”. This successful use of DNA evidence is seen in the Frank Alan Button case. Frank Button was convicted of raping a 13-year old girl by a jury in August 1999. Initially, the girl denied knowing the rapist and provided a description of the man to the police. She then, altered her original statement and identified Frank Alan Button as her rapist. During the trial, no DNA evidence was used. A rape kit was prepared and intimate swabs were obtained from the victim. These tests revealed the

There are often mistakes made that falsely determine an individual’s sentence. Sloppy police work and loss of documents are examples of careless errors. There is also some room for error with determining the results of a DNA sample that do not fall under the human error category. Many times there may not be ample DNA samples at a crime scene. Only a fraction of crimes reveal DNA. Drive-by shootings and bombings often do not provide DNA for investigation purposes. “There is a public perception that DNA is the cure-all for these kinds of mistakes. DNA is not the whole answer.” (Dieter, Richard) Eye witnesses cannot solely and accurately determine a person’s fate 100 percent of the time. There are numerous amounts of cases in which those found guilty were indeed later found innocent. Many times, these individuals have already served time in jail. Many argue that the time inmates spend in

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