DNA evidence: Helpful, harmful to defendents?
The methodology is not always reliable
Isabell Rivera OW Contributor | 6/27/2019, midnight
The thought of going to trial and being prosecuted without any DNA (deoxyribonucleic acid) evidence seems unthinkable in 2019, but sometimes DNA evidence can actually be more harmful than helpful. In many cases that come to trial, DNA evidence plays a key role, next to confessions, and eye-witness testimonials. However, it’s up to the judge and the jury how much weight DNA evidence receives in comparison to confessions and testimonies.
Since DNA is only 99.9 percent identical—which means we share DNA with everyone else—it’s the 0.1 percent that make us individuals, and therefore unique. With that said, it’s never really a 100-percent match.
According to experts, “while DNA is extremely good at identifying individuals, mistakes have happened. Accurate identification is dependent on a number of factors, including the quality of the DNA sample, the number of genetic markers analyzed, whether the sample was prepared properly, and the ability of those doing the analysis to interpret the results.”
Of course, any discussion of DNA evidence harkens back to the O.J. Simpson case. Although Simpson’s DNA and that of Nicole Brown and Ron Goldman was found at the crime scene and at Simpson’s residence, the forensic work was handled sloppy, causing cross contamination with DNA of the victims, suspect, and the LAPD.
The mishandling of DNA evidence is one of the issues that could lead to errors in finding the suspect. Since DNA travels through talking, sneezing, touching various objects, hugging strangers or shaking hands, it can therefore place a person at locations (or before people) they haven’t visited physically. DNA is also shed through losing hair or skin cells, for some people more than others. An average person may shed up to 50 million skin cells a day.
However, when it comes to DNA testing, a dozen or more genetic markers in the code are used to identify important aspects, such as differences and similarities between people.
According to experts, “The more markers used, the greater the accuracy, but also the cost of testing. The probability of the DNA profiles of two unrelated individuals matching is on average less than one in 1 billion. Even advanced DNA testing, which allows the recovery of minute traces of DNA, cannot prove how the DNA got to a crime scene.”
A good example for DNA transfer is the case of Lukis Anderson. Anderson, a Black homeless man with an alcohol problem, tends to sometimes “blackout” while drunk. But did he commit murder? When he got the news that his DNA was linked to a robbery-homicide case more than 10 miles from his location, he was shocked and confused, but didn’t doubt that he might have done this while being blacked out. It didn’t help either that Anderson had quite a rap sheet full of petty crimes, which put his DNA into the database, and being a minority and homeless made him to be more of a target.
Somehow, Anderson’s DNA got transferred onto a homicide victim, Ravesh Kumra.
But Anderson had an alibi. On the night of the robbery-homicide, Anderson decided to get drunk and pass out at the store, where the manager called for an ambulance. After the paramedics helped Anderson—who was a familiar face—they received a phone call to go to the residence of Raveesh Kumra, the homicide victim, which likely resulted in the DNA transfer either because of a pulse oximeter slipped over both patients’ fingers, the uniforms of the paramedics, or another piece of equipment. While the actural reason for this circumstance remains unclear, it became apparent that Anderson had nothing to do with the case.