Feces, DNA, and Identifying Perpetrators of Crimes



Deoxyribonucleic Acid or DNA can be found in many types of biological forms of evidence. From saliva, to blood, semen, urine, and sweat, DNA profiles can be developed, connecting perpetrators of crimes to crime scenes and crime victims. In Lakeville, Indiana, three construction workers were murdered at a construction site. Police had little to work with and no leads in the case. However, one investigator observed someone on the property recently stepped in a pile of dog feces. The footwear left a clear impression in the feces. It was determined that the footwear that made the impression was not from anyone residing on the property or the construction workers. The impression was captured through photography, and a sample of the feces was collected.

With no leads, days passed until a call came in from someone advising they believed they knew who was responsible for the killings. With a possible suspect identified, investigators obtained a search warrant for the apartment where the suspect lived. Police found a pair of shoes with what they believed was a matching tread pattern, and one of the shoes just happened to have what appeared to be dog feces in the shoe tread. While the footwear impression and tread pattern could be an important match to the impression left at the scene, a DNA match would prove stronger evidence. The investigator began to inquire if this evidence could be tested for possible DNA, and contacted the University of California, Davis. DNA evidence had been used in the past for animal cases, but never in a murder trial.

Investigators swabbed the cheeks of the homeowner’s dogs and submitted the swabs and feces samples to the laboratory. The lab was able to generate DNA profiles for the dogs from the swabs, but had never used dog feces to generate a profile. DNA is not present within human or animal feces, but can be on the outside of the sample. As fecal matter exits the body, it slides along the walls of the tube, which can lead to cells being transferred to the sides of the sample.

The process lab workers used provided a match between the fecal matter on the sidewalk outside the home under construction and the fecal matter in the tread of the suspect’s shoe, placing him at the scene of the crime. Gang member Phillip Stroud and his accomplices were arrested, tried, and convicted of the triple homicide due to Stroud accidentally stepping in the dog feces during the commission of the crime.

Comments

Post a Comment

Popular posts from this blog

Image
Forensic Knowledge Test: What do the terms Cause, Manner, and Mechanism of Death mean? Also, by what means can investigators and medical examiners determine the Postmortem Interval (PI), or the approximate time of death of a victim? (Mount Wachusett Community College, 2022) Following the death of an individual, medical examiners and investigators must determine the cause, manner, and mechanism of death. The process is conducted to provide a final determination on the case and to allow investigators to close the case, or continue the investigation.  When we refer to cause of death , we are referring to the reason the person died. Disease, physical injuries, a stroke, poisoning, and a heart attack can all be considered causes of death.  Manner of death refers to the ways in which a person can die, and there are four manners of death. These manners are (1) natural death, (2) accidental death, (3) suicidal death, and (4) homicidal death. Undetermined can also be used if a medical...
Read more
Image
Forensic Entomology and the Death Scene The dead can no longer speak for themselves. It is the job of the crime scene investigator to identify, document, collect, and preserve evidence of crimes that speak for the crime victim. In many cases, nature provides that evidence for investigators. Upon death, the body of the deceased immediately experiences physiological changes and begins the decomposition process. As the body decomposes, a common and predictable sequence of insects inhabit the body; this process is known as insect succession. Insects such as flies, wasps, beetles, and ants quickly attack the body if the deceased is not in a secure environment. Forensic entomologists identify insects from the crime scene, using accumulated degree hours (ADH) to estimate an approximate time of death. The ADH information allows forensic entomologists to estimate the time involved in developing the current stages of insect succession, in accordance with local conditions. It is the predictable p...
Read more