How Does DNA Work in Criminal Cases in Minnesota?
We’ve all watched crime shows where some criminologist comes in, usually with lots of tattoos and multi-color hair, holding a sheet of paper that definitively identifies “the killer” or “the rapist” or “the bank robber.” Case closed, right? Not so fast. While DNA can be compelling, it is absolutely not definitive. If DNA is critical in your case, then, read on. Contact an experienced criminal defense attorney with extensive experience handling DNA.
“DNA is only as good as the process used to find, save and test it. After all, junk in, junk out.”
How Exactly Does DNA Evidence Work in Minnesota Criminal Cases?
DNA is the basic building block of life. DNA stands for deoxyribonucleic acid and it is a very common tool used by law enforcement in a large number of criminal cases to identify individuals here in Minnesota. The process of profiling individuals using DNA is relatively new and has been developing since the mid 1980s. When used correctly, DNA can be quite successful in identifying individuals or related individuals. While there are several labs, the biggest here in Minnesota is the Bureau of Criminal Apprehension in St. Paul.
DNA is made up of four types of building blocks called nucleotides. It is this combination of these nucleotides, adenine, cytosine, guanine and thymine that creates the DNA instruction book. While this in itself makes it sound simple, it is anything but. Every human contains about 3 billion bases and about 20,000 genre and 23 pairs of chromosomes. Hence, this is why it took so long to develop this method.
DNA exists in the cells of all organisms including people. Here is how it works. Law enforcement collects human cells for DNA and send the material to a crime lab. The lab technicians can then create a DNA profile for that person. Only a tenth of on 1% of human DNA differs from one person to another and that as of today, DNA testing is about 95% accurate. However, this assumes that all protocols were correctly followed in terms of both collection, storage and analysis.
Where Does DNA Come From and Why Does it Matter?
Let’s start at the cellular level. DNA evidence can be found everywhere in a human body, So, this means blood, semen, saliva, teeth, hair, skin, tissue, feces. fingernails are all possible sources for DNA evidence.
An interesting facts of human bodies is that they have a tendency of sluffing off enormous amounts of DNA. They may leave it where they sleep, sit, what they touch, what they wear, in the car they drive. A lot of it may be in dead skin cells. Pretty disgusting, right?
As a result, police officers collect lots of evidence at crime scenes out of the hope that a person of interest may have touched or been near an item and left samples of their DNA behind. Places where DNA may be found may include obvious places like on guns, knives, condoms but in may also include clothes, hairbrushes, eyeglasses, cups and laundry. This can be very important as it may be able to place a specific person at a specific location. This may be critical as part of building a case.
“While DNA may place an individual in a particular place, it is critical to understand the differences between primary, secondary and tertiary DNA.”
How Does Law Enforcement Use DNA?
The study and analysis of DNA has changed a lot since the mid-1980s. Since then, law enforcement has established multiple databases for comparative purposes. There is the FBI National DNA Index System (NDIS) and other accredited organizations who help set standards. They also connect with the Combined DNA Index System (CODIS) which shares its information with law enforcement across the country and right here in Minnesota.
So, law enforcement here in Minnesota may go to a crime scene and collect DNA for analysis. That DNA would then be sent to a crime lab such as the Bureau of Criminal Apprehension (BCA) in St. Paul, MN. The lab will extract the DNA and then compare it to other known samples that they possess or they may compare it to other samples on CODIS.
The end result may be an identifier of DNA in a particular spot and potentially at a particular time with up to 95% of accuracy. Under certain circumstances, this result can be devastating such as in rape cases and ID cases. However, it does have its limitations. It doesn’t explain how it got there, just that it is there. This distinction may be critical to a case. Think contamination? Think user error? Think tertiary DNA?
Does Chain of Custody Really Matter in Minnesota?
In a word, yes. Chain of custody establishes a step-by-step, individual-by-individual, unbroken line between when the evidence was collected all the way up until when the evidence is presented at trial. It establishes who touched it, who had access to it, where it was located, and the condition of it all along the way. If the evidence was handled improperly or contaminated in some way, a good criminal defense attorney may be able to exclude it from evidence. While the fewer people that touch it the better, it is also important to consider documentation. If the evidence isn’t tracked, identified, protected, and documented between each and every interaction, it may also be excluded from evidence to be presented at court. The idea that “the evidence seems fine” simply shouldn’t cut it.
Assuming everything is done perfectly, chain of custody and a sufficient quantity of material was collected, DNA can be quite accurate. However, understanding this process and its weaknesses is where a discerning criminal defense lawyer in Minnesota may be the most helpful.
Go with the Best
If you are facing serious criminal charges in Minnesota and those charges involve DNA as an identifier, contact an experienced criminal defense attorney immediately. Jack Rice is a Board Certified Criminal Law Specialist, a former prosecutor, a former U.S. Federal Agent and the Founder of Jack Rice Defense. Contact Jack Rice Defense for a free confidential consultation or call 651-447-7650 or 612-227-1339.