September 10, 2012 Warm-up: Use pg. 13 in your text book to answer the following question: 1.What was the most significant modern advance in forensic science? 2.Who is accredited with this and what did he do? Copy the Notebook Check List on the following slide

Intro & Forensic Science History Notebook: 1.Anthropology Skull Activity 2.Lab Safety Rap 3.Lab Safety Fill-In-The-Blank 4.Forensic Science History Notes (Part 1 & 2) 5.“Deadly Picnic” Activity 6.“That’s My Story & I’m Sticking To It” 7.Forensic Science History Quiz 8.Crime Lab Units (17 total) 9.Chapter 1 Reading Guide 10.Locard’s Exchange Lab 11.Scientific Method & Rules of Evidence Notes

The Scientific Method: A Framework for Testing Evidence Scenario: During a bank robbery shots were fired both by the suspect and a bank guard. During this crime, a patron lying on the floor between the two was shot through the leg. The bullet was recovered from the victim’s leg at the ER and sent to the forensic lab. Both the bank guard and the suspect deny shooting the victim but both had a 9mm automatic pistol which were also sent to the lab. Who is telling the truth? How would you use science to examine the evidence from this case?

The Scientific Method 1. State an hypothesis 2. Design an experiment 3. Make observations and record data 4. Analyze and interpret the data 5. Draw a conclusion 6. Define the next question

The Scientific Method 1.State an hypothesis (What is the question that the evidence needs to answer?) – “I think that this bullet came from that gun.” – “I don’t think that this bullet came from that gun.” – formulating a hypothesis is not bias although bias can cause the wrong question to be asked “How did O.J. kill Nicole Brown Simpson & Ron Goldman?” (wrong) “Did O.J. Simpson kill Nicole Brown Simpson & Ron Goldman?” (appropriate)

The Scientific Method 2.Design an experiment to test the hypothesis – compare the bullet microscopically with other test bullets known to have been fired from each gun

The Scientific Method 3. Make observations and record data – photograph the questioned & reference bullets through the microscope – record the number of features in common how many where they are located

The Scientific Method 4. Analyze and interpret the data – bullet comparison analysis – scrutinize the marks to determine if any differences between the questioned and known bullet are not relevant to the comparison interpretation – how many marks need to be similar between the evidence bullet and a test bullet to convince the examiner that the bullet could or couldn’t have come from another gun

The Scientific Method 5. Draw a conclusion at the end of the experiment – data must be summarized – a statement of the meaning or the data in the context of the hypothesis must be made – “the number of similar marks are sufficient to declare that both bullets came from the same gun”

The Scientific Method 6. Define the next question – often the answers obtained generate more questions – the next set of experiments is planned

Which part of the Scientific Method tests the hypothesis? Designing an experiment

Skills of a Forensic Scientist Must be skilled in applying the principles and techniques of science to the analysis of many types of evidence. Participate in training law enforcement personnel in the proper recognition, collection, and preservation of physical evidence. Provides expert court testimony.

Skills of a Forensic Scientist An expert witness is an individual whom the court determines possesses knowledge relevant to the trial. The expert witness is called on to evaluate evidence based on specialized training and experience. The expert will then express an opinion as to the significance of the findings.

Determining admissibility of evidence – Frye standard In order to be admitted as evidence at trial, the procedures/tests used must be “generally accepted” by relevant members of the scientific community. – Federal Rules of Evidence More flexible than Frye standard, many states follow this guideline Governs admissibility of all evidence Rule 702 – States witness “qualified as an expert by knowledge, skill, experience, training, or education” can offer testimony on scientific or technical matter if… » Testimony is based on sufficient facts or data » Testimony is the product of reliable principles and methods » Witness has applied the principles and methods reliably to the facts of the case

- Daubert Case - Frye Standard (general acceptance) is not an absolute pre-requisite to the admissibility of scientific evidence – Trial judges assume the ultimate responsibility to serve as “gatekeeper” when deciding the admissibility and reliability of evidence presented in court.

Providing expert testimony – Expert witness – an individual whom the court determines to possess a particular skill or knowledge in a trade or profession that is not expected of the average layperson and that will aid a court in determining the truth of a matter at trial – training and years of experience are two major considerations – problems of sorting out the strengths and weaknesses of expert testimony falls to prosecution and defense counsel – Expert witness is called on to evaluate evidence when the court lacks the expertise to do so, then expresses an opinion as to the significance of the findings.