Forensic Science
Application of science to matters of the law
Observation
Use of one or more of the senses to learn something about the surroundings, a person, or an object
Observations and the Brain
We constantly collect information but our brains apply a filter to that information. Sometimes we have sensory overloads, fill in gaps we have in information, and apply previous knowledge to new situations
Eyewitness Accounts
Reports from individuals often vary and depend on levels of stress, concentration, beliefs, etc.
Innocence Project
Created by Barry C Scheck and Peter J Neufeld in 1992. The project re-examines post-conviction cases using DNA evidence. False eyewitness testimony contributed up to 87% of the convictions in over 200 cases they studied.
Memory Efficiency
An eyewitnesses memory of an event depends on level of interest, stress, concentration, distractions, prejudices, beliefs, motives, and lapse in time since the event.
Role of Forensic Scientist
To find, identify, document, and interpret evidence
Documentation
A forensic scientist must document everything because memory is faulty
Serology
Study of body fluids (blood, etc.)
Toxicology
Study of poisons and their effects (drugs, etc.)
Chemistry
Study of composition of properties of substances (analysis of drugs, arson, explosives, etc.)
Questioned Documents
Study of documents (ink, paper, handwriting, watermarks, etc.)
Fingerprint Analysis
Study of fingerprints (classification, individualization, visualization, preservation, etc.)
Firearm Analysis
Study of firearms and related evidence (bullets, etc.)
Trace Evidence Analysis
Study of trace evidence (hairs, fibers, soil, paint, glass, pollen, dust, etc.)
Tool Marks Analysis
Study of tool marks (impressions made by objects that come into contact with other objects)
Forensic Odontology
Study of teeth
Forensic Entomology
Study of insects
7s's
Secure the scene, separate/interview the witnesses, scan the scene, see the scene, sketch the scene, search for evidence, secure and collect evidence
Securing the Scene
Responsibility of first responder. Must provide medical attention to injured persons. Post tapes, ropes, and barricades around perimeter of scene to exclude people who are not directly involved in the investigation.
Separating/Interviewing Witnesses
Asking witnesses standard questions to help investigators reconstruct the crime and corroborate information about the crime.
Scanning the Scene
Determines where photos should be taken and may identify primary and secondary scenes.
Seeing the Scene
Starting with close up shots of significant aspects of the scene and then moving to photographing key pieces of evidence and finally the entire scene using a wide angle lens.
Sketching the Scene
Initial sketch of the scene first which is not neat but should be as detailed as possible.
Searching for Evidence
Find the perpetrators path of entry/exit and locate pieces of evidence. The specific search patterns can vary but no area should be left unsearched.
Securing and Collecting Evidence
Evidence must be properly packaged, sealed, and labeled but not all evidence is packaged in the same way.
Crime Scene Personel
Police officers, district attorney, crime scene investigators, medical examiners, detectives, and any specialist necessary.
Rough Sketches
Sketch should include fixed points for scale, labels on every item, accurate dimensions of objects, case information (date, time, location, case #, and sketcher's name), and compass direction north.
Smooth Sketches
Should omit lines, labels, and numbers but should include numbers denoting objects/evidence, legend identifying numbered items, scale, compass direction north, and case information.
Two Dimensional Sketches
Incorporates walls and ceiling by creating a map of the 3D space.
Search Patterns
Line, spiral, and grid for large areas or outside. Quadrants or spiral used for small areas such as rooms
Locard's Exchange Principle
Fundamental concept of forensic science created by Dr. Edmond Locard in 1910. States that "when a person comes into contact with an object or other person a cross-transfer of physical evidence or trace evidence can occur.
Trace Evidence
Hair, soil, blood droplets, paint chips, etc.
Physical Evidence
Fingerprints, shoe prints, tire impressions, tool marks, etc. All of these excluding fingerprints reduce the number of suspects
Biological Evidence
Body fluids, hair, plant parts, etc. All of these may make the group of suspects vary small or reduce it to a likely suspect.
Direct Evidence
First hand observations such as eyewitness accounts or police video.
Circumstantial Evidence
Indirect evidence that can be used to imply a fact but not directly prove it. Further broken down into physical and biological.
Chain of Custody
Process that incorporates documentation of who, when, or where of a piece of evidence from it's collection to it's final disposition. Disruption of this documentation could result in the evidence's inadmissibility during court.
Proper Packaging
All evidence is packaged differently.