DNA Based Conviction Case Study

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.

This report acts as guidelines for handling post-conviction DNA testing. These guidelines explore the legal and biological issues. Also, a set of guidelines are recommended for prosecutors, defense counsel, judiciary, victim assistance and laboratory assistance. This report also examines the impact on DNA testing on exonerations.

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.

The fundamental DNA-based conviction in the United States happened not long after in 1987 when the Circuit

I. Before the 1980’s, courts relied on testimony and eyewitness accounts as a main source of evidence. Notoriously unreliable, these techniques have since faded away to the stunning reliability of DNA forensics.

One of several errors in the trial was a reckless omission by a forensic scientist who testified for the prosecution. Semen was found on the victim’s body, the scientist testified, and Dominguez’s blood type matched the semen sample, meaning he could have been the perpetrator. The scientist did not tell the jury, however, that two-thirds of men in America would have matched that sample. Dominguez was convicted and sentenced to nine years in prison. He was released after serving four years and sought DNA testing at his own expense. The tests proved his innocence. His case is one of many in which limited forensic science or wrong forensic testimony has led to wrongful convictions.

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.)

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

In March of 1985, Bloodsworth was sentenced to death. Through it all Bloodsworth maintained his innocence and in 1993 with the help of a new technique used to test for DNA, Bloodsworth got his chance to prove he was innocent. Bloodsworth became the first person ever to be exonerated from death row by DNA evidence. (Jain, 2001) In one

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 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

DNA testing became more prominent in 1989 and defendants that were once found guilty were being exonerated. Gary Dotson was the first to be incarcerated in 1979 due to serology evidence collected blood typing was conducted. After several years, of false imprisonment, further testing was done by conducting a Polymer

and could get up to 50 years in jail if convicted of rape and kidnapping.

“In 1984, a British geneticist named Alec Jeffreys stumbled upon one of our most important forensic tools: DNA fingerprinting. Since his “eureka moment,” the scientific technique has been used successfully to identify perpetrators of a crime, clarify paternity and exonerate people wrongly convicted” (Jones). DNA evidence, specifically simple-mixture, is the most accurate type of forensic evidence we currently have at our disposal, but even it is not infallible. Other types of forensic evidence are much less accurate, but unfortunately their use is still permitted in U.S courtrooms. Jurors may be misled by experts within the courtroom as well. These misconceptions about the accuracy of forensic science and the field in general lead to many problems in the courtroom.

investigations both past and present. It can be used to identify criminals when there is evidence