Latent Impressions In Homicide Scene Analysis

crime scene could be analyzed and compared with a sample from a suspect. A match could place

It’s important that all evidence is identified so that forensic scientist can examine it and take

11.) Use a clean laboratory spatula to place small amounts of the sample from the suspects shoe in wells M,N, and O. Record the physical properties you

The purpose of this experiment was to investigate a crime scene. Given an evidence bag a number of tests were performed in order to determine who the suspect was. The experiments included a simple fiber burn test, iodine fuming to develop a finger print, and thin-layer chromatography to determine ink similarities.

I read Eric the Warning to Motorist from a pre-printed form at 1840 hours. Eric agreed to provide a urine sample at 1845 hour, which I was present for the voiding of the bladder. The primarily result were positive for opiates. The urine sample was inventoried to be sent to the State of Illinois Crime Lab. He agreed to perform a breath test, which I administered 1905 hours, I am a certified breath operator and the results were (.000).

crime scene. Loose hair and blood spatter are to be collected for testing because at first

After leaving from behind the counter I being to look for more evidence and find A crude map and directions to the store drawn/written in pencil on a piece of notebook paper on the floor. I feel that this evidence could be processed at the scene for prints with the basic powder procedures. Nothing really hard for this one because the suspect could have touch it and left behind some form of trace so checking it wouldn’t hurt.

The main provision in all cases is the avoidance of including fingerprints to evidence, or of ruining the ones already existing at the time. Once the crime scene has been carefully recorded and each of the evidence located have been annotated, then the process of gathering and analyzing can commence. The crime scene investigator will start by collecting the most delicate and easily prone to be lost evidence. Locating latent fingerprints at the crime scene requires use of techniques that makes it ideal for visibility. Investigators will use a several of methods to visualize the print, however it will depend on the surface that print is being lifted from. All non-movable and fixed items at a crime scene sustained to be handled on the scene using one of

As chemist with forensic case work and field experience, I know low-cost and low-tech methods of analysis are in demand. While such methods are typically presumptive in nature, they play a vital role in both lab and field analysis. Presumptive tests allow users to triage samples for confirmatory analysis, saving time and expense. Whether a crime scene, combat zone, or natural disaster site, presumptive assays influence command decisions. In technology deficient areas, presumptive assays may be the totality of the analysis available. Most presumptive tests are color tests, providing a visual cue to the user as to the presence of a particular compound (1-2). While color tests have their benefits, a big drawback is the false positive (3), i.e. the erroneous “compound is here”. My research focuses on minimizing false positives, false negatives, and generally improving the selectivity of color tests without sacrificing their ease-of-use and low cost.

Describe examples of three biological specimens that can be analyzed using toxicology to provide evidence in a criminal case.he three specimens and describe how they are tested. The three specimens I chose are hair, blood and bile. Hair is tested for arsenic. This is because arsenic if ingested too quickly is excreted through the hair and fingernails. It can be detected over a long period of time after death. Approximately 100-200 mg of hair should be collected from the vertex posterior on the back of the head by cutting as close to the scalp as possible, ensuring that it is clearly marked which end is closest to the scalp and appropriately securing the hair into a bundle with a rubber band, twist tie, or string. Blood is tested for illicit

The collection of fiber evidence takes extra care. The examiner must use gloved fingertips with a clean set of tweezers or forceps. (Trace Evidence, 2013) Nevertheless, a vacuum fitted just for individual fiber collection is used in case the fiber is loose. (Trace Evidence, 2013) However, the examiner must keep each article of clothing, or other object separated and packaged carefully in paper bags to avoid cross-contamination. Each garment should be laid on a clean sheet of paper, and separately rolled up in the paper after marking the exhibit. (Crime Scene Resources,2016) "If the clothing of one subject touches the clothing of another, or if it is laid down on the table or placed on the car seat contacted by the clothing of the other suspect, the comparisons may be of no value" (Crime Scene Resources, 2016). “Scrupulous care must be taken to prevent articles of clothing from different people or different locations from coming into contact” (Saferstein, 2015, p.252). However, certain items such as carpets, rugs, and bedding must be folded carefully to protect areas suspected of fiber evidence. A car seat must be covered with polyethylene sheets to protect fiber evidence, and knife blades should be covered as well to protect alleged fiber evidence. (Saferstein, 2015) If a body was wrapped in a blanket, rug, or carpet, an adhesive tape is used to lift the fibers exposed on the body areas. (Saferstein, 2015) Fibers that need to be removed from an object must be covered with clean forceps and placed on a small sheet of paper folded and labeled and then placed inside a container. (Saferstein, 2015) Finally, fibers are delicate and must be taken care of before

Footprints and tire marks are one of the most commonly pieces of evidence that is found at a crime scene. The impressions of the footprint at the crime scene can be compared to suspect’s

Collecting gunshot residue (GSR) is very vital and major piece of evidence in a case. It impacts the case dramatically. For example the case I choose the shooter was convicted because of the GSR test that was conducted. The gunshot residue was on a glove found on the suspect as well as gunshot residue on Males t-shirt and pant leg of suspect. Without this evidence four child and her family would have never got justice for their mother Ansari death that they deserve. Males was sentenced to 53yrs. To life. I hope he is in prison for life for killing an innocent person. This assignment shows the importance of gunshot residue testing on a

Today, more than ever, the quality of evidence in criminal cases is scrutinized because of contamination. Contamination is the introduction of something that physically corrupts a substance at a crime scene that was not previously there; it comes in many forms and most often times comes from the humans who investigate a crime scene. It is imperative that prevention of cross-contamination is implemented when gathering evidence. Several of the more sensitive forensic techniques such as trace analysis, bloodspatter interpretation, and DNA comparison are not being used to their fullest potential. Items of physical crime scene evidence are not always visible to the naked eye and may be easily overlooked so deliberate and methodical approach to collection and preservation of evidence is essential. Prosecutors have lost cases due to crime scene contamination; this could be prevented by simple and productive behaviors. The U.S. Supreme Court, in a leading case on physical evidence, stated:

Impression evidence is where several objects are pressed or stamped together allowing the objects to transfer and retain characteristics from one another. Pattern evidence is additional identifiable information found within a piece of impression evidence. Many times investigators will find fingerprints, shoe prints, or marks of a bullet at a crime scene. Evidence such as this is fairly easy to identify. Many times crime scene investigators can walk on to a crime scene and spot them easily.