Criminal trials have changed dramatically since I tried my first case in Seattle Municipal Court in July, 1977. With the exception of an occasional murder trial, most cases back in those days did not involve forensics.
I also recall that the detectives who worked homicides and assaults appeared to have little concern about introducing trace evidence and foreign substances into a crime scene by tracking it in on their shoes or boots. They were permitted to smoke while collecting evidence and thought nothing of leaving their cigarette butts at the crime scene. I was never certain whether the hairs they collected at the crime scene were there before they arrived or whether they unintentionally introduced them into the environment at the crime scene via shedding after they arrived.
I hate to admit it, but all of the lawyers I knew back then, including myself, were scared to death of math and science. For example, most of us decided to go to law school because we wanted to earn graduate degrees. We decided on law school because we had convinced ourselves that we could not make it through any graduate degree program that involved math or science.
Like most lawyers, I assumed that forensic scientists were basically honest and I did not question or challenge their assumptions and opinions. Instead, I accepted their opinions as unassailable and developed trial strategies to work around them.
I began to question the validity of my irrational fear of math and science in the early 80s around the same time that scattered reports of forensic fraud started appearing in the news. I remember reading about Dr.Jeffrey’s efforts in England to apply laboratory methodologies to extract human DNA from biological evidence recovered at crime scenes. Although promising, the major problem with his method, which was called RFLP testing, was that it required larger amounts of pristine DNA than were typically recovered at crime scenes.
A few years later, I read about a new method of typing DNA called PCR testing that was developed by Dr. Kari Mullis. His method mimicked the process of cell division by creating millions of copies of targeted sequences of DNA that could easily be typed thereby eliminating the need to recover large biological samples from crime scenes. In fact, the method was so sensitive, simple, and effective that it could create enough copies to accurately type the DNA obtained from a few cells.
I soon realized that PCR’s unique ability to accurately type vanishingly small quantities of human DNA was also its greatest weakness because it would also create millions of copies of DNA from another human source inadvertently and accidentally introduced into a crime scene by a detective collecting evidence, or into the testing process in the lab by a laboratory analyst. I recall that I was stunned by the possibilities.
My comfortable views regarding how to try cases was shattered and from that time forward I made it my business to learn all that I could about forensic science and to use that knowledge trying cases.
That brings me to today’s subject for discussion. I have noticed y’all discussing the crime scene investigation conducted by the Sanford Police Department and wondering to what extent, if at all, they screwed it up. Assuming they did, the next question should be whether their screw-ups were material? In other words, will their screw-ups affect the outcome of the case?
To aid you in evaluating the efforts of the Sanford Police Department, I am going to turn you on to a treasure trove of resources that I am sure you will want to bookmark and explore in the future.
Follow this link to learn more more about crime scene investigations.