Dr. Bettie Davis
Assistant Professor, Chemistry, St. Vincent College
Chemistry and Crime
When a person registers to vote, their name is place in a pool of potential jurors, and they may, at some point, be called to serve on a jury. In a culture saturated with literature, movies and television programs, how is a the average citizen to decide between fact and fiction when it comes to scientific evidence presented in a trial, where the jury’s decision can have profound consequences for a person’s life? Chemistry and Crime is a course for non-science majors at Saint Vincent that looks at the chemistry behind major crimes (such as arson, drugs, or murder) and the science underlying the analysis of evidence. Scientific concepts are introduced in class through the context of a number of forensic cases. Students also encounter cases from the Innocence Project as a way to understand the multiple ways that evidence is and isn’t used. In the laboratory students test various materials and carry out different procedures that reveal the limits of scientific evidence. By the end of the course, students will have a stronger grasp of the nature of scientific evidence and their responsibilities as a juror.
By the end of this course, each student should be able to:
- identify and understand the basic chemistry behind evidence collection and testing;
- objectively think about evidence presentation and how this evidence could affect the outcome of a trial.
- have greater awareness of the serious responsibilities that jurors are charged with in the justice system.
Students enter the class thinking that they are taking a course that will mimic the TV series CSI. By the time the course is over students will see that:
- What is on television is not real. For example, you do not have DNA results while the body is still on the autopsy table. Students do not realize how long some of the tests take and are upset when they find out that the results are not ready within 2-3 hours.
- Test results are not always accurate. Too often the interpretation of results are largely subjective and not objective. Even when a test is done in a scientific manner, the results may not be accurate.
- The criminal justice system is not always just. Evidence can be mishandled, not tested, or withheld from lawyers. If people are convicted and new evidence comes to light, the person who has been convicted may or may not be given a new trial. There is no uniform process.
- Lawyers and the public generally do not understand science or the scientific method. Either they fear it or believe it to be infallible. If evidence is presented, it may not be presented in a way that people fully understand.
- If a person has registered to vote, that person can be called as a potential juror. That juror holds someone’s life in their hands. If called to serve as a juror, how does a person ensure, to the best of their abilities, that the verdict is a proper verdict?
Student Learning Objectives
- knowledge of basic scientific concepts important in the analysis of forensic evidence;
- application of these concepts to specific cases;
- understanding of the relationship between the scientific methods used in forensics and the ethical/legal dimensions of their use
- capacity to assess the quality and relevance of evidence, and arguments derived from it, in the context of forensic investigations;
- enhanced problem solving, observational, and critical thinking skills.
Students often remark that after taking the class they realize that there is a big difference between fictional presentations of forensic procedures and reality. For example, evidence does not immediately become part of a trial process, but may actually take months to years to be presented. We all have the right to a speedy trial, but that may or may not happen. The justice system claims to be fair and honest, but there are many political, cultural, and individual factors that can negatively influence the process. The students leave the course realizing that if the criminal justice system is to be improved, and always reflect the principles we claim it is based on, citizens, as jurors or voters, will be important agents in making the needed changes.
Linking Science and Social Issues
The following science concepts are introduced through a series of actual forensic cases in the textbook (one case per chapter); the textbook author regularly updates some cases for each new edition of the textbook. The case descriptions below reflect those in the third edition of Investigating Chemistry by Matthew Johll.
Introduction to Forensic Chemistry:
scientific method, physical evidence, skill of observation
taught through the case of a farmer murdered in Illinois where the issue of planted evidence was critically important in the resolution of the case
Chapter 2 – Evidence Collection:
physical properties/density, measurement, significant figure, basic calculations, accuracy and precision
taught through the case of Tommy Pitera, a Mafia member, who was eventually convicted of multiple murders in part through soil analysis.
Chapter 3 – Atomic Clues
atomic theory and structure, isotopes, interaction of light and matter, electron configurations
taught through a case in Dublin, Ireland where isotopic analysis was key to identifying a murder victim
Chapter 4 – Chemical Evidence
types of compounds, chemical reactions, balancing chemical reactions, stoichiometry
taught through a case involving thallium poisoning
Chapter 5 – Chemistry of Bonding
chemical bonding (ionic and covalent), polarity of molecues, shapes of molecules
taught through a murder involving insulin overdose
Chapter 6 – Properties of Solutions 1
aqueous solutions, solution concentrations, acid/base chemistry, pH
taught through a case involving the dumping of pollutants into the White River (located in Indiana)
Chapter 7 – Properties of Solutions II
intermolecular forces, dissolving soluble compounds, colligative properties (freezing point and osmosis in conceptual rather than mathematical terms)
taught through a case involving the theft of Demerol and its replacement with saline solution
Chapter 8 – Drug Chemistry
introduction to organic chemistry
taught through the case of Charles Cullen, a nurse who used the drug digitalis to murder at least 40 hospital patients
Chapter 9 – Arson Investigation
combustion and oxidation/reduction reactions, thermochemistry
taught through the case of Kenny Richey, initially convicted of arson and murder and sentenced to death but ultimately exonerated 21 years later.
Chapter 10 – Chemistry of Explosions
taught through the challenge of detecting explosives at airports
Chapter 14 – DNA Analysis
DNA structure/function/analysis, mitochondrial DNA
taught through the analysis of the remains of victims from the September 11, 2001 destruction of the World Trade Center
In addition, there are several other cases not found in the textbook that are used in the course:
- The O.J. Simpson case as a context for understanding how a crime scene should not be handled and the importance of documentation by both police and laboratory workers.
- A crematorium that buried over 300 bodies in an unmarked mass grave rather than cremating the bodies as they claimed as a context for the use of elemental analysis.
- John George Haigh, a British serial killer active in the 1940’s, as a context for acid-base chemistry (Haigh disposed of the bodies of his victims by using an acid bath to dissolve them).
- Timothy Spencer, an American serial killer who committed three rapes and murders in the Richmond Virginia area, as a context for DNA analysis (Spencer was the first murderer convicted with the use of DNA evidence).
Chemistry and Crime Syllabus
Chemistry and Crime Laboratory
NSCI 210 (lecture) This is a non-major science course which will focus on the chemistry concepts of forensic science. These concepts will help explain how various forms of evidence can be left at the scene of a crime, how the evidence is found, and how the laboratory can determine the relevancy of that evidence. We will be studying basic chemical principles such as chemical bonding, solubility, and the structure and function of organic molecules. This course does not require math skills beyond pre-algebra. Offered spring semester. Three credits.
NSCI 211 (lab) This lab provides the student basic methods dealing with evidence collection and analysis. We will look at the chemical analysis of fingerprints, paints, fluids, and many other types of evidence which can be collected and analyzed. Must be taken simultaneously with, or after successful completion of NSCI 210. Offered spring semester. One credit.
In addition to several exams during the semester, there are several “real world” assignments that students complete which are described below.
The third exam is one that, historically, students do not perform as well on as they do on the first two exams. So after the third exam is completed, I use a case from the National Center for Case Study Teaching in Science as a quiz for extra points on that exam. Before giving the case, the students have watched the film After Innocence, which is described on its website http://www.afterinnocence.net as:
“the dramatic and compelling story of the exonerated – innocent men wrongfully imprisoned for decades and then released after DNA evidence proved their innocence. The film focuses on the gripping story of seven men and their emotional journey back into society and efforts to rebuild their lives. Included are a police officer, an army sergeant and a young father sent to prison and even death row for decades for crimes they did not commit.
The men are thrust back into society with little or no support from the system that put them behind bars. While the public views exonerations as success stories – wrongs that have been righted – AFTER INNOCENCE shows that the human toll of wrongful imprisonment can last far longer than the sentences served.”
In class we have just explored DNA, how it can be used in the criminal justice system, and how the justice system sometimes does not use properly the information found in DNA. This particular case is a clicker case where the students work in pairs and answer the questions as they appear. The answers to all of the questions are given in the details of the case, so the students must pay attention to the story line.
(case can be found at http://sciencecases.lib.buffalo.edu/cs/collection/detail.asp?case_id=725&id=725)
Online Fourth Exam
For the fourth exam (the last one during the semester), I have the students bring one laptop per pair of students to class. They are told in advance that this exam will be an online test. As they enter the classroom I have posted the following link: http://chemcollective.org/mr/
The students follow the death of a graduate student and subsequent investigation including suspect interviews and evidence collection. Using the analysis of the evidence carried out by a “virtual” forensic laboratory as well as the interviews, the students fill out a form that identifies who they think the murderer is, what evidence they used to identify this person, how the crime was committed, and what further studies need to be done.
Instead of a final exam, I have students work in groups to develop a final presentation. Each group is required to examine a case from the current news or from The Innocence Project. The presentation is to consist of an introduction to the crime, evidence collection and testing, court proceedings and an examination of strengths and weaknesses of the American Judicial System.
Criteria used in evaluating final presentations include
Name the case or the book
Give a background of the case
Give a synopsis of the evidence used for the case
How was the evidence analyzed
What scientific principles were used
What scientific principles were not used
What was the verdict
How was the evidence used to convince the jury
Was this a valid verdict
Has the case been reviewed
What was done to change or confirm verdict
What was the final outcome
Who Killed the Mayor?
By the end of the semester the students in the lab course have gained experience with fingerprinting, hair and fiber analysis, blood typing and grouping, and plaster impressions. The final laboratory activity requires that students put all of the skills that they have learned in lab into practice. I use a kit from Carolina titled “The Case of the Murdered Mayor” (catalog # 699830). In this activity, students assume the role of crime scene investigators as they use their observational skills and deductive reasoning to solve a realistic crime scenario. They attempt to identify a prime suspect from a pool of 6 alleged perpetrators using these traditional forensic techniques:
- Hair analysis (requires low-power microscope, not included)
- Tire track impression analysis
- Blood typing (using synthetic blood)
- Forensic entomology (with artificial fly larvae or maggots)
- Police log review
At the end, students write a report to the District Attorney regarding who should be arrested for the crime.
Background and Context
The course was developed because of a need at Saint Vincent College for more courses specifically for non-science majors. It was first offered in spring 2010 and, while the original plan was to offer the course every other year, it has been offered every spring because of student interest/demand. A few years after the course was first offered, the College launched a new major in Criminology, Law, and Society; the director of that program highly recommends that students in that major take the course.
The course is designed to partially fulfill the natural science requirement in Saint Vincent’s Core Curriculum, which requires every student to complete eight credits in natural sciences.
Scientific literacy is demonstrated when a person can:
- Describe the nature of scientific knowledge, use the scientific method, and comprehend, present and critique scientific work;
- Explain the most fundamental observations and models developed in the process of scientific inquiry;
- Evaluate the impact science has had on the human condition.
- “Form habits of ordered inquiry, logical thinking, and critical analysis.”
- Analyze the reasons leading to specific ideas;
- Evaluate the views of others based on appropriate evidence;
- Use directly collected data or data given to construct knowledge by organizing (synthesizing, sequencing, or interpreting) the new information with previous background;
- Critically review habitual assumptions in order to accommodate existing beliefs and assimilate new knowledge
The course has been presented as a talk at the 248th National Meeting of the American Chemical Society held in August 2014.