Guy Paul Morin Justice System: A Case Study

Forensic Problem The justice system is in place to put criminals behind bars. However, sometimes the justice system fails us. Guy Paul Morin is just one of the victims of the justice system. On October 3, 1984, nine-year-old Christine Jessop disappeared after being dropped off at home by the school bus. When her parents came home and realized that she was not at home, they called the police. Her body was found on December 31, 1984 and revealed that she had been stabbed to death. Investigators also found semen stains on her underwear. The police first became interested in Guy on February 14, 1985, when Christine’s mother referred to Guy as a “‘weird-type guy’ who played the clarinet” (Harland-Logan, 2016). They set up surveillance of the Morin

The hair shaft is composed of three layers – the cuticle, cortex, and medulla, and is subjected to the most forensic examination. “The cuticle is the scale structure covering the exterior of the hair” (Sauer, 2016a, Slide 9) and the cuticle in human hair is usually made of small, flat scales. This distinguishes the hair from animals, as animals have cuticles that are triangular in shape or that are shaped like a crown (Lerg, 2012). Furthermore, “the cortex is the main body of the hair shaft” (Sauer, 2016a, Slide 15) and is embedded with the pigment granules that give hair its colour. This helps investigators compare hairs of different individuals. Additionally, “the medulla is a cellular column running through the center of the hair” (Sauer, 2016a, Slide 17). The medulla in a human hair is usually less than one-third the diameter of the shaft, while for animals it is usually one-half or greater (Lerg,

STRs are loci on the chromosome that contain short random repeats. STRs normally consist of repeating sequences of 3 to 7 bases in length, and the entire strand of an STR is also less than 450 bases in length. One of the main reasons DNA analysis on the semen stains was possible after so many years was because STRs are less susceptible to degradation and can be recovered from stains subjected to extreme decomposition. During the examination THO1, a commonly used STR with the repeating sequence of AATG, is extracted, amplified by PCR, and separated by electrophoresis. The process for STR analysis requires polymerase chain reaction (PCR), which is a technique for replicating small quantities of DNA. In addition, during the process electrophoresis is used for separation, which uses thin tubes instead of flat gels (Sauer, 2016b, Slide 45-55). STR analysis allowed investigators in the Guy Paul Morin case to test the DNA evidence on the underwear, which proved Guy’s