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ACT: Forensic Science – Fact or Fiction?

ACT: Forensic Science – Fact or Fiction?. A single investigator trained in forensics can collect & analyze all evidence from a crime scene. FICTION!

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ACT: Forensic Science – Fact or Fiction?

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  1. ACT: Forensic Science – Fact or Fiction?

  2. A single investigator trained in forensics can collect & analyze all evidence from a crime scene. • FICTION! • Usually, law enforcement collects evidence, whereas highly trained lab-based analysts from various disciplines can conclusively examine evidence. • Forensics scientists usually specialize in one area of expertise (i.e., fingerprints, firearms, DNA)

  3. Blue (UV) lights are useful tools at a crime scene • FACT! • Saliva, urine, & semen will fluoresce under a UV light, even if they are not visible to the naked eye • Blood, however, requires the chemical luminol, not UV light, to luminesce.

  4. Advanced DNA analysis automatically identifies an individual within minutes • FICTION! • Even the simplest DNA analysis can take hours to complete, though typically labs take 30+ days to analyze DNA • The FBI’s CODIS (Combined DNA Index System) doesn’t store personal data with the DNA; that must be looked up in separate databases

  5. All fingerprint records are stored in AFIS (Automated Fingerprint Identification System). • FICTION! • Only individuals arrested of crimes and who apply for civil employment or licensing screens are stored in the FBI’s AFIS. • There are other AFIS systems at local, state, and federal levels that may have other records. • The system isn’t as “automated” as you may think!

  6. A trained crime scene investigator can usually identify an unknown powder by sight, smell, or taste • FICTION! • Analysts should NEVER directly smell or taste unknown substances due to danger of potential poisons! • Instead, they use field equipment to run presumptive tests. Only an empirical test can conclusively identify a substance.

  7. An IP address can determine who sent an email • FICTION! (mostly) • An Internet Protocol (IP) is like a phone number; it can track an email back to the router it came from, but it still takes good old fashioned detective work to put a suspect “at the keyboard.”

  8. You can match a bullet with the gun that fired it. • FACT! • When a gun fires a bullet, it leaves behind a unique pattern of striations. • However, if a gun has been altered after firing or if the bullet is badly damaged, it may be impossible to match

  9. DNA analysis saves lives. • FACT! • To date, over 250 people have been saved/exonerated of wrongful convictions by the Innocence Project, who offer DNA analysis. • However, DNA analysis has also ruined lives due to mistaken results (though odds are low)

  10. All evidence that is collected at a crime scene is tested in a lab. • FICTION! • In a perfect world with an unlimited budget and man hours, all evidence WOULD be tested in a lab. • However, over 500,000 cases in the U.S. are backlogged in crime labs! • One estimate indicates an additional 1,900 full time employees would be needed to meet the number of 30 day turnaround requests submitted in a year.

  11. There is forensic evidence in every case • FICTION! • Some evidence is not suitable for analyses; environmental conditions or time could have destroyed or degraded it, certain tests are destructive & inconclusive, some evidence is difficult to find, crime scenes & evidence may be contaminated, evidence can be lost or stolen, etc.

  12. Teeth are trustworthy evidence. • FACT! • Dental records are used to identify 93% of remains! • Teeth are often well preserved for long periods of time and provide unique imprints useful in classifying remains

  13. Deleted computer files are gone forever. • FICTION! • Deleting a file on a computer simply hides it, and marks it as data waiting to be rewritten • Computer analysts have programs to copy and read this hidden “deleted” data

  14. Everything you do on the internet is tracked. • FACT! • Every site you visit, every key stroke you make, every click of the mouse, can be traced by a computer technician. • If they wanted to, the government can track the internet activity of anyone.

  15. Forensics not only helps people, but the Earth, too. • FACT! • Mismanagement of hazardous waste, large-scale industrial pollution, and other serious eco-crimes can now be solved through the efforts of forensic scientists. • Wildlife forensic scientists also help to stop poaching, thus protecting biodiversity.

  16. Forensic Science dates back to the 1700s. • FICTION! • One of the earliest accounts of forensic science used to solve a crime occurred in 44B.C., when Julius Caesar was murdered. • A physician named Antistius determined which Roman senators were responsible for the stabbing death of J.C. and were sentenced to death

  17. BONUS FACT! • The physician Antistius made his fateful announcement in the Roman forum, giving forensic (from the Latin forensis, “belonging to the forum”) science its name.

  18. ACT: Eyewitness Observations

  19. Eyewitness Observations • Often, investigators rely on eyewitness testimony to help them better understand a crime scene or catch a suspect. • On the next slide, you will have 30 seconds to examine a picture. Commit as many details to memory as possible (without writing them down or taking photos). Following the 30 seconds, you will be asked a series of questions regarding what you observed.

  20. Eyewitness Questions • Are there cars parked on the sides of the road? • What color is the pickup truck driving in the road? • Any minivans around? • What does the blue sign say? • What’s the speed limit? • Are there any pedestrians on the road?

  21. How’d You Do? • As you discovered, you may have forgotten some details, or perhaps remembered other details incorrectly. Your own memory can sometimes fail you!

  22. Multiple Witnesses • But, what about other people’s memory? In this next activity, different people will observe the same scene. Does it help to have several witnesses? • Select one person in your lab group to be an investigator and the rest will be eyewitnesses. • The investigator will go out in the hall for 30 seconds while the eyewitnesses observe a photo (no notes or photos allowed).

  23. Investigators, ask your eyewitnesses questions about the scene they just observed. • From their accounts, create a sketch and detailed reconstruction of the scene. • Ready to see how well you did…..?

  24. Compare the comments and observations of each eyewitness. How many details were mentioned correctly? • How many details were omitted? • How many statements conflicted with one another or the truth? In what way? • Is having multiple eyewitnesses better or worse than an individual eyewitness? Why?

  25. TedED • Forensic Science: The problem with eyewitness testimony (20:50min) • https://ed.ted.com/on/nknoKe22#review

  26. Discussion • If it is not entirely trustworthy, should eyewitness, testimonial evidence be allowed in criminal cases at all? Why or why not? What rules would prevent it from being misused to convict innocent people? • Discuss in lab groups & prepare a whiteboard to present to the class.

  27. Scientific Method and Deductive Reasoning for Forensic Science • OBSERVE a problem or questioned evidence and collect objective data. • Construct a HYPOTHESIS or possible solution to the problem based on observation, giving direction to the work plan. (*This step requires inductive reasoning, experience, and imagination!!) • EXAMINE, TEST, AND ANALYZE to support or refute the hypothesis. • Use DEDUCTIVE REASONING to make a determination as to the significance of the evidence. • EVALUTE AND VERIFY all evidence. All possible errors must be stated (since someone’s liberty depends on this!). Consideration must be given to standardization, reproducibility, validity, reliability, and accuracy.

  28. Deductive Reasoning • Have you ever played the board game Clue™? In the game, players gather information in order to determine the murderer, murder weapon, and crime scene. Actually, participants are not “guessing” when they play this game; they are using deductive reasoning. As players gather more information, they begin to put together the pieces of the mystery. • Police investigators follow a process similar to that used in Clue™. The investigators collect and evaluate evidence from a crime scene. All the information they gather is compiled and placed in the criminal case file. As new evidence become available, it is added to the file. • Police investigators rarely learn about events in the same sequence in which they took place during the crime. Usually the leads are acquired in random order. Once a large portion of information is known, the police experts must sit down and put the pieces together, like you would assemble a jigsaw puzzle. • Deductive reasoning is the thought process that police investigators use to assemble the pieces of the criminal puzzle and reach a logical conclusion. In deductive reasoning, investigators utilize logical and critical-thinking skills to reach a conclusion.

  29. Deadly Picnic Take-Aways Which woman/women had... Means (ability). Who was capable of producing and using the gun? • Rita – most likely • However, any of the women may have likely been able to get a gun. Opportunity (can be placed at scene). Who has an alibi for the killing and therefore did not have opportunity? • Peggy is deathly allergic to grapes (wine). • Lauren has large feet, the shoe prints found are too small to be hers. • Janice teaches aerobics on Friday night; hates yellow; nonsmoker • Gail hates yellow; at aerobics on Friday; nonsmoker • 2nd most likely suspect - Rita never wears lipstick; lives in the country *Motive (reason). What was the motive?

  30. Which woman do you think killed Mr. Brooks? • ELAINE is the most likely suspect • She lives downtown • She is a size 4 and would likely have small feet (size 5) • She is Peggy’s roomate Elaine and Gavin Brooks had a date for a picnic on Friday night. They brought a sheet, food, and wine. Mr. Brooks most likely picked up Elaine and drove her to the picnic area in the country. Elaine was possibly jealous of Mr. Brooks’ relationship with her roommate and intended to get back at him by shooting him while on their date. After Elaine shot Mr. Brooks, she drove herself back to town and abandoned his car in a vacant parking lot.

  31. In order to prove guild in a court of law, you must prove: • Means (ability) and opportunity(can be placed at scene). • opportunity is most often disproved by an alibi. • You do not need to prove motive, but it can certainly help your case. How sure are you of your suspect’s guilt? Would you feel comfortable convicting any of the women in this case based on the evidence you had? Do you think the crime was premeditated? Why or why not?

  32. Understanding the Law • Homicide: the act of one human killing another • Murder: • First degree murder: the premeditated, unlawful, intentional killing of another person; and • Second degree murder: The intentional, unlawful killing of another person, but without any premeditation. • Manslaughter • Voluntary - the offender had no prior intent to kill and acted in "the moment", under circumstances that could cause a reasonable person to become emotionally or mentally disturbed. • Assisted suicide • Involuntary - is the homicide of a human being without intent, either expressed or implied • Constructive manslaughter - also referred to as "unlawful act" manslaughter.  • Criminally negligent manslaughter- occurs where death results from serious negligence • Vehicular or intoxication manslaughter

  33. Defenses to homicide • Not all homicides are crimes, or subject to criminal prosecution. Some are legally privileged, meaning that they are not criminal acts at all. Others may occur under circumstances that provide the defendant with a full or partial defense to criminal prosecution. Common defenses include: • Self-defense: or “stand your ground” defense (often includes the right to defend others) • Mental incapacity: in the United States, the death penalty cannot be applied to convicted murderers with intellectual disabilities. Instead, the individual is placed under the category of "insane". • Defense of infancy - Small children are not held criminally liable before the age of criminal responsibility. • Justifiable homicide or privilege: For example, a killing on the battlefield during war is normally lawful, or a police officer may shoot a dangerous suspect in order to protect the officer's own life or the lives and safety of others. Source: https://en.wikipedia.org/wiki/Homicide

  34. Forensic Science Acronyms & Abbreviations

  35. AFIS - Automated Fingerprint Identification System ALS - Alternative Light Source ATF - Alcohol, Tobacco, & Firearms BAC - Blood Alcohol Content BAU - Behavioral Analysis Unit CIA - Central Intelligence Agency

  36. CODIS – Combined DNA Index System CSI - Crime Scene Investigation DEA - Drug Enforcement Agency DOA - Dead On Arrival FBI - Federal Bureau of Investigation FDA – Food and Drug Administration

  37. GSR - Gun Shot Residue IBIS - Integrated Ballistics Identification System LD50 - Lethal Dose that kills 50% of sample MO - modus operandi or Mode of Operation NCIS – Naval Criminal Investigative Service Perp - Perpetrator

  38. STR – Short Tandem Repeat TOD - Time of Death UnSub - Unidentified Subject ViCAP – Violent Criminal Apprehension Program

  39. Introduction to Forensic Science and the Law

  40. I. Introduction: Definition and Source • Definition: Forensic Science is the study and application of science to matters of the law (criminal and civil). • Source –From the Latin word “forensis” which means forum. The Forum was a public gathering place during Roman times, where judicial activities and public business was conducted.

  41. II. History and Development Forensic Science Many believe Sir Arthur Conan Doyle had a considerable influence on popularizing scientific crime-detection methods through his fictional character, Sherlock Holmes. • Alphonse Bertillon (1853-1914), French Scientist: • 1879, devised first system of person ID using a series of body measurements • Francis Galton (1822-1911), British Scientist: • 1892, “father of fingerprinting,” published the book “Finger Prints” which contained the 1st statistical proof supporting the uniqueness of fingerprints. • Leone Lattes (1887-1954), Italian Scientist: • 1915, devised a procedure by which dried bloodstains could be grouped as A, B, AB or O • Edmond Locard (1877-1966), French Scientist: • 1910, formulated the Locard’s Exchange Principle – “Every Contact Leaves a Trace”

  42. Locard’s Exchange Principle • When a criminal comes in contact with an object or person, a cross-transfer of evidence occurs • The criminal either removes something from the crime scene or leaves something behind • Either way this exchange can link the criminal to the crime scene

  43. III. Organization of the Crime Lab • General Information: • 1910 - First police crime lab was established in France by Edmond Locard • 1923 - First police crime lab in the U.S. opened in in Los Angeles, CA • 1932 - The first FBI crime lab opened in Quantico, VA

  44. Services Provided by Full-Service Crime Labs • Physical Science Unit – use chemistry, physics, and geology techniques to compare and identify evidence from a crime scene. • Biology Unit – in charge of DNA profiling on dried blood stains and other body fluids. • Firearms Unit – examine all types of evidence that have to do with firearms. • Document Examination Unit – examine handwriting and typewriting on suspicious documents to determine the validity and source of the document. • Photography Unit – “record” (photos) physical evidence from a crime; analyze the photos. • Fingerprint Unit - process and examine latent fingerprints. • Toxicology Unit (optional) –  examine body fluids and organs to determine the presence or absence of drugs and poisons in an individual's body. • Polygraph Unit (optional) – administer and interpret lie detector tests • Voiceprint Analysis Unit (optional) – forensic scientists try to trace voices to specific suspects if the case involves telephoned threats or tape-recorded messages

  45. Other Forensic Science Fields • Forensic Anthropology – apply skeletal analysis and techniques in archaeology to solving criminal cases. • Forensic Psychiatry – determine whether or not an individual has the ability, mentally, to make specific decisions or to stand trial. • Forensic Odontology – identify victims based on dental evidence. • Forensics Engineering – work with failure analysis, accident reconstruction, and causes and origins of fires or explosions. • Digital Forensics – identify, collect, preserve and examine evidence from computers and other digital devices. • Wildlife Forensics – use scientific procedures to investigate wildlife-related crimes involving the exotic pet trade, poaching, other illegal hunting activities, and even oil spills.

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