Post-conviction exoneration case studies

Michael was a navy sailor before he was arrested for murder. He was accused of murdering a young woman after raping and severely injuring her on the head and neck. The woman, Linda broke her jaw and spine during the incident. The original evidence for the trial was obtained after an analysis was done on the semen which was found on Linda’s body. The procedure then was to collect sample of semen from Linda’s anus, vagina and vulva. The matching of blood groups revealed that the semen matched with Shirley’s blood group which was by then shared between about 23. 3% of British men.

Vital information came from the shoe-mark that was imprinted on Linda’s stomach which corresponded with Shirley’s and some cuts and scratches on his face which were presumed to have arisen from an attack. Forensic DNA information was with the police at the time of Shirley’s trial. DNA fingerprinting eliminated the first suspect from legal proceedings and linked Colin Pitchfork who had committed two murders. DNA profiling to support investigation could not be taken due to insufficient semen to allow blood group analysis.

With the advancement of PCR amplification smaller and degraded specimens could be used to obtain full genetic profiles (Shirley, 2003). According to Shirley (2003), it was the year 1999 when a DNA analysis using very small samples was done to previously stored samples. This analysis was inconclusive due to absence of samples from both parties. After two years samples were obtained from the mouth of each but failed to match with those of the victim or the convicted assailant. In July, 2003, the Court of Appeal reversed the conviction although many features lacked which were necessary during the technical and scientific investigation.

The documents that were made available could not state the gene loci with clarity. Also the laboratory technique which was applied in the test could not be ascertained. The Crown did not differ with the analysis results obtained but many technical aspects remained missing from the judgment passed by the court. This case therefore comprises more of a science advancement case rather than a case of exoneration. Value of DNA evidence According to Keith and Rudin (1997), DNA has been used as an investigative tool which is very powerful since it certifies that besides identical twins, it is not possible to have people with the same DNA.

It is on this fact that DNA can either incriminate a person or can exonerate him from crime. In a case involving a sexual violation, evidence can be obtained from biological specimens such as skin cells, blood, hair and semen. If the DNA is properly collected, it can be compared with predetermined samples to incriminate a person in crime scene. DNA profiling is usually done through entering the information into FBI records called Combined DNA Index System (CODIS). This can help trace a suspect from any part of United States. This is usually done in case there is no suspect who has been arrested in connection to the crime.

Effective use of DNA information as evidence entails collection of samples which are then analyzed to determine their source. Other samples called elimination samples are taken from people who legally accessed the crime scene since they may have left their own marks. This is done to prevent incriminating them unfairly. In cases involving rape, it is imperative to obtain samples from people who have engaged in sexual intercourse with the victim within the last three days of the alleged crime. It is through a thorough comparison of DNA profiles that preponderance of evidence can be justified.