 OBJECTIVE: Examine physical evidence and its uses in a court of law.  1. Question of the Day  2. Chapter 2 TESTS  If you need to take the test, do so now.  3. Introduce Chapter 3: Physical Evidence  4. Homework and Review

CHAPTER 3

 Every crime scene needs to be treated on an individual basis.  Certain types of evidence are likely to yield significant results in ascertaining the nature and circumstances of a crime.  Responsibility of the investigator to be familiar with  Recognition, collection, and analysis of items  Laboratory procedures and capabilities

 Evidence can be overlooked.  Collected evidence can be left on the evidence room shelf.  Never examined or processed.  Regulations apply to the admissibility of evidence.  Generally begins at time/date a crime has been reported  Official police inquiry/investigation

 Any objects that can establish a crime has been committed.  Evidence can provide a link between a crime, the victim, and the perpetrator.

 Biological evidence was collected from a crime scene. It places the suspect at the scene of the crime where a murder had taken place. Under cross examination, the forensic specialist who had collected the sample admits that he may not have followed the correct procedures to collect the evidence. The crime lab technician testifies under oath that the results of analytical testing of the evidence is 100% accurate.  Predict the outcome of the trial. Justify your answer.

 The evidence will be removed from the trial as per a judge’s ruling.  The jury will be instructed to disregard this evidence.  Provide an example of the technician not following the proper procedures when collecting evidence.  Think like the DEFENSE!  What other problems might this create for the prosecution?

OBJECTIVE: Explain the value in the proper collection, processing, and examination of evidence as used in a court of law.  1. Chapter 2 TESTS  2. Types of Physical Evidence  3. Case Study  4. Review and Homework  CASE STUDY QUESTIONS  Project Deadline 1

 Explosives – any device containing an explosive charge  Includes any object at or removed from the scene of an explosion  Suspected to contain residue from an explosion or use as a detonation device  Fibers – any natural or synthetic fiber whose transfer may be useful in establishing a relationship between object or persons  Cotton, silk, nylon, spandex, kevlar, as well as glass and metallic fibers  Fingerprints – all prints of this nature both visible and latent

 Firearms and Ammunition – any firearm as well as discharged or intact ammunition suspected of being involved in a criminal offense  Spent casings and recovered bullets or “slugs”  Glass – any particle or fragment that may have been transferred to a person or object involved in a crime.  Includes windows/panes of glass containing holes made by bullets or other projectiles  Hair – any animal or human hair present that can link a person to a crime

 Blood, semen, and saliva – can be dried or in a liquid state, human or animal.  Subjected to biochemical and serological analysis to determine identity and possible origin  Documents – any handwriting or typewriting submitted to confirm the authenticity or source  Paper, ink, processed  Drugs – any substance seized in violation of laws regulating the sale, distribution, manufacture, and use of drugs

 Impressions – tire markings, shoes prints, depressions in soft soil/sand, and all other forms of tracts.  Gloves, fabric impressions, and bite marks in skin, foodstuffs, and other objects.  Organs and physiological fluids – tested drugs and poisons as well as blood to be analyzed for alcohol/drug content.  Urine, vomit, bile  Paint – any liquid or dried paint that may have been transferred from one object to another during the act of a crime  Transfer of paint from one vehicle to another in a car accident

 Petroleum products – any product removed from a suspect or recovered from a crime scene.  Gasoline residues or grease and oil stains  Plastic bags – polyethylene disposable bags such as garbage or shopping bags.  Examined/chemically analyzed to associate a bag to similar bags at a crime scene or possessed by a suspect.  Plastic, rubber, polymers – remnants or residues of man-made materials may be linked to objects relevant to a crime scene or suspect.

 Powder residues – any item suspected of containing firearm powder residues.  Serial numbers – stolen property submitted for the restoration of damaged/erased ID numbers  Soil and minerals – any object that could link a person to a particular location  Tool marks – impression marks found in an object caused by a “tool”.

 Vehicle Lights – examination of a vehicle’s headlights and taillights to determine their use at the time of an accident/impact.  Wood and other vegetative matter – wood, sawdust, or vegetative matter discovered on clothing, shoes, or tools that could link a suspect to a crime location.

 Investigator must be able to  Make logical decisions  Process the uncommon and unexpected  Qualified evidence collectors must also be able to make innovative and on-the-spot decisions at the crime scene.  Standardized set of procedures  In the best interest of the investigation  Always within the clear definitions of the law

 1. Physical – A physical object or something residing on a physical object.  2. Personal – A description or account of what has been seen or heard.  3. Circumstantial – Evidence that requires an inference (conclusion based on evidence).  Indirect evidence that implies something has occurred  Does not prove it  Leads to/connects other facts/circumstances together

 Prepare a scenario to give an example of circumstantial evidence.  Write it down.  You will be volunteered to share your examples.

 Woman accused of embezzling money from her company.  Makes big ticket purchases in cash around the time the money was taken.  A man is accused of stealing valuables from a house.  His wallet and license are found on the front lawn of the house.  Does not prove the robbery but could be implied because there is no other logical explanation as to why the man’s ID is at the crime scene.

 Individual  Associated with a common source and high degree of probability.  Fingerprints  Class  Associated with a group and a low degree of probability.  Difficult to determine exact source of evidence.  Blood types, carpet fibers

 Inceptive  At the start of investigation  Evidence to establish the need for an investigation  A search for a perpetrator  Corroborative  At the end of an investigation  Evidence used to prove or disprove  Generally, the key piece of evidence to link a suspect to a crime

 Identify or compare the evidence.  Identification – process of determining an object/substance’s physical or chemical identity.  Certainty as to composition of specimen  Exclude all other possibilities Problems – each type of evidence requires different tests Each test has a degree of specificity 1 test versus 5 tests to ensure accuracy

 Dependent upon type of evidence 1. Hand written ransom note  Handwriting analysis 2. Drugs  Bench tests – physical tests (Chemistry Class)  Computer based Analysis – Chromatography Spectroscopy

 Collected specimen and control specimens  Both evaluated under same set of tests and examinations  Must be scientifically accepted and proven techniques  Determine if they have a common origin  Consider chemical composition  Produces highest degree of Probability

 Define each of the following and provide an example of each one.  1. Class evidence  2. Personal evidence  3. Circumstantial evidence  4. Corroborative evidence  5. Individual evidence

 Two potential suspects are in custody for an armed robbery. Both claim they are innocent and have alibis. Suspect A states that he was home all night. Suspect B states that he ate dinner at a local restaurant and then took a train out of town. The only evidence is an eye-witness account who claims to have seen a man fitting their height, build, and hair color.  How would you go about collecting additional evidence to find out if either suspect is responsible for the crime.

 Suspect A  Did any neighbors see him?  What did he eat for dinner?  Food delivery  Look through garbage  Did he make any phone calls (phone records)?  Was he using his computer?  Playing video games?  Suspect B  Which restaurant?  Speak with st aff  How did he pay (date/time on receipt)?  Train ticket/receipt?  Did he travel to the destination he claims?  Confirm this with who he visited.  Purpose of trip out of town.