Research Ism

Marina Fick ISM- Period 6 Layton, Julia. “How Crime Scene Investigation Works.” HowStuffWorks Science, HowStuffWorks, 31 Oct. 2018, <science.howstuffworks.com/csi4.htm>. • • • • • • • • • • • • • • • • • • • • • •

For trace evidence tweezers, containers with lids, vacuum devices, and a knife may be used to collect it Gloves should be worn but sometimes boots, face masks and gowns can be worn Clothing may be taken from a victim or someone present at a crime scene if a gun was involved in order to test for GSR GSR can tell many things like potential suspects and the distance from which someone was shot Evidence like clothing should be stored in paper/evidence bags Illegal drugs should be collected using a knife and then properly stored More than likely stored in a sterile container A lot of trace evidence can be found in places that most people would not think about Examples include: shaking out bedding, clothing, towels, couch cushions, and other furniture/items Body fluids can be collected using smear slides, a scalpel, tweezers, scissors, sterile cloth squares, a UV light, protective eyewear and luminol Luminol is a chemical that can be used to view if a crime scene was cleaned up by reacting with the chemicals in cleaning products Getting DNA from potential suspects or just people from the crime scene is a good because it allows you to compare DNA samples This comparison lead to finding a suspect Scraping a victim’s nails for skin is another good way to find suspects because if there was a struggle then there may be skin under the nails from the struggle Dried blood is another form of evidence that will be submitted to a lab for testing Blood splatter patterns cannot always pinpoint a suspect but they can give information over what occurred at a crime scene Examples: what weapon was used, from what distance the weapon was used, direction of the blood and weapon, and much more Hairs and fibers can be collected using combs, tweezers, containers and vacuum devices Fingerprints, footprints and documents are all valuable sources of evidence as well Powder, chemicals and fuming can be used to lift fingerprints off of surfaces Molds can be made of footprints but footprints are hard to collect sometimes Documents can be evidence because they can give information over things like why someone may have died, who might have committed a crime, when a future crime may take place, etc.

This source provided a good list of information over all the different types of evidence and the different techniques/tools used by CSI’s to collect the said evidence.

Marina Fick ISM- Period 6 “Reconstructing a Crime Scene.” UniversalClass.com, www.universalclass.com/articles/law/reconstructing-a-crime-scene.htm. • • • • • • • • • • • • • • • • • • • • •

"the use of scientific methods, physical evidence, deductive reasoning and their interrelationships to gain explicit knowledge of the series of events that surround the commission of a crime"- Association for Crime Scene Reconstruction Crime scene reconstruction is not a perfect retelling of the crime but it can help investigators to figure out what happened and how it may have happened Before reconstructing a crime scene, the physical evidence found at the crime scene must be analyzed Witness accounts and other factors must also be taken into account/ analyzed Photographs, physical evidence and an autopsy report are essential for investigators to come up with a hypothesis of what could have occurred at the crime scene In the 1990’s crime scene reconstruction was first introduced There are different types of crime scene reconstruction Incidents like a homicide or death investigation would be a specific incident reconstruction When an investigator wants to know the order in which something occurred, they would use a specific event reconstruction Bullet/missile trajectories, blood splatter analysis and other physical evidence are useful for reconstructing a crime scene Impressions and glass fragments are also useful in reconstructing a crime scene Some investigators may choose to use video graphic software to see a crime in a threedimensional way When in court there is either demonstrative or real evidence that the investigator has to be able to tell the difference between Real evidence is actual physical evidence (evidence that you can touch physically) Demonstrative would be the actual crime scene reconstruction because it is a demonstration that is usually used to help a jury or judge understand what occurred at a crime Demonstrative evidence can also be animations, some photographs, videos, diagrams, documents, etc. The tricky thing with dealing with demonstrative evidence is making sure that it is verified, authentic and/or accurate Non-accurate evidence will not be used in court and if it is then this can cause an investigator to lose their job or possibly indict an innocent person Knowing things about a victim helps investigators to accurately recreate the crime scene Things that are important to know about the victim include: health records, wound patterns and their mind set/thinking (victimology) Knowing a victim’s daily patterns and place of employment is also valuable information

This source went very in depth about the many different procedures that crime scene investigators go through before they can adequately reconstruct a crime scene.

Marina Fick ISM- Period 6 “Crime Scene Investigation.” Crime Scene Investigation: Principles, www.forensicsciencesimplified.org/csi/principles.html. • • • • • • • • • • • • • • • • • • • • • • • • • • •

“whenever someone enters or exits an environment, something physical is added to and removed from the scene”- Locard’s Exchange Principle “Every contact leaves a trace” -summary of Locard’s Exchange Principle Evidence that can link someone to a crime scene is called associative evidence Associative evidence includes things like hair, fibers, DNA evidence, etc. The main purpose of this evidence is to tell investigators who was at the crime scene or who committed the crime Reconstructive evidence tells investigators how something may have happened Reconstructive evidence is collected when a crime scene is reconstructed Substances found at a crime scene like control samples are also good for using to link people to crimes If a control sample is found on a suspect’s skin, clothes, etc. then that can link them to a crime and possibly indict them For example, glass fragments have specific patterns that can be matched to each other This kind of evidence can also rule people out or prove them innocent Tread impressions are also good examples of evidence that can link someone to a crime Tread impressions can be shoe prints, tire tracks, etc. When an investigator finds evidence, they must consider the possibility that the evidence may just be there by coincidence The chances of a DNA sample being coincidental are very low Items that are inconsistent with the surrounding area are key pieces of evidence Inconsistent items are good for linking people to crimes If a suspect has something that matches an item at the crime scene this can link them to the crime and it becomes an essential piece of evidence The type of case being investigated will determine what type of evidence is going to be collected The case will also determine what evidence is deemed more important to the case Some cases make it more difficult for investigators to collect evidence For example, a body found buried somewhere where they were not killed will probably not have much evidence This would be an example of a secondary crime scene because the crime did not occur there Digital evidence can also be used to link people to crimes Digital evidence includes things that are found online or on a computer Written documents can also link people to crimes This can be a journal or a written statement etc.

This source had good explanations over how the different types of evidence can link a suspect/person to a crime and the source also described what evidence is what.