Forensic Significance and Examination of Faecal Matter

Faecal matter is an often overlooked but possibly significant piece of evidence. It is found in a variety of casework scenarios, ranging from trace amounts to whole stool deposits. Small amounts of faeces can be transmitted to the sodomite’s penis or other objects introduced anally in circumstances of sexual assault. In contrast, a criminal may purposely or unintentionally defecate at the site of a crime, leaving behind an entire bowel movement. In many situations, the identification and individualization of faeces can establish a relationship between the victim and the perpetrator. Animal metabolism produces faeces as an excretory by-product. It is made up of bilirubin, muscle fibres, and undigested cellular and vegetable material. Its identification may occasionally be quite important, particularly in sodomy situations. For more than a century, faeces have been examined as part of criminal investigations. In particular, faecal analysis was used in 1948 to connect a suspect's shoes to a crime scene in a burglary case. Finding a connection between the reference sample and the faecal evidence is one of the goals of faecal analysis, which could help connect a suspect to a crime scene. The identification of faecal matter is valuable in providing important information for a criminal investigation. For example, the presence of faecal matter may corroborate a sexual assault involving sodomy, assault with faecal matter, vandalism, bestiality, and burglary during which the perpetrator defecated at the scene, faeces can be found as evidence on the penile swab and in the clothing. If faeces are already present at the crime scene, faeces may be transferred to the suspect's shoes or clothing. In sodomy and bestiality, the suspect’s faeces play a key function in determining his or her drug habit. It has also been noticed that the ingestion of certain medicines causes faeces to turn green, black, and red. Alkaline phosphatase, IgA immunoglobulins, intestinal parasites, pancreatic-amylase, urobilinogen and urobilin, and vegetable remains have been analysed as part of forensic methods for the characterization of human faeces. It can also be utilised for blood grouping, hence aiding in the individualization of individuals. Today, the forensic DNA analysis of sloughed intestinal epithelial cells seen in faecal debris may efficiently determine the unique properties of a faecal sample as it enables nuclear DNA-based discrimination and CODIS comparison.