The many misunderstandings of scienceSunday, November 28, 2021
My entry into training in law enforcement began as a forensic investigator over two decades ago at the Metropolitan Police Institute in Miami, Florida. This is the training academy for the Miami Dade Police Department.
I was not exactly ignorant of this area of science when I began. I had been a trial investigator for years. There were quite a few areas of the science I was sure I knew, till I opened a textbook and I realised many things I thought were facts were fables.
This is the reality of many areas of science, especially those related to law enforcement.
You see, television and movies have impacted us all. We see murders being solved in an hour on a regular basis, usually based on some scientific tool and the brilliance of some serious sleuth.
So let us look on the oldest fable first — fingerprints.
Fingerprints are unique to each and every individual. They are formed in the womb based on the movement of the feotus. No two babies move in the exact same way whilst in their mother's stomach. So we can agree that they are in fact unique and an incredible tool for identification.
The misunderstanding is their ability to transfer them to a surface. The likelihood differs per surface. One such surface that is extremely difficult for transference of fingerprints to take place is a firearm.
Nationwide, laboratories in the United States have an average 10 per cent success rate of detecting fingerprints on firearms that they know where touched.
The danger here is that juries made up of normal people who watch a lot of crime dramas do not know this fact.
I imagine judges do. But is it because of their efforts or is it part of their mandated training?
Then there is gunshot residue, the famous gunshot residue that you must have once you fire a gun. More nonsense! They had discontinued this test by the time I started studying over two decades ago in the United States because it was causing acquittals of guilty perpetrators.
That gunshot residue starts to dissipate very quickly so if you do not have a swabbing done between 15 and 45 minutes you may not detect it.
This is also impacted by the movement of an injured person or if the hands were bagged within minutes of the shooting.
Yet to many members of the public, juries and jurists included, it is looked on as a foolproof test, when it is in fact very unlikely to detect elevated levels on someone tested over an hour after the firing of a weapon, of less than three rounds.
Then we have bite mark evidence. This rubbish has sent more guys with crooked teeth to jail than racist juries.
There is nothing unique in the configuration of your teeth and the ability to accurately transfer a mark that can be scientifically linked to a set of teeth is subjective. But to many out there “it's foolproof”.
I could go on and on but editorial word count would not allow me to examine every area of science that is misunderstood and impacting courts worldwide to include our own.
The matching of hammer-forged barrels to recover fired bullets by our own forensic lab has resulted in two acquittals of police officers in recent times, not because they did the matches and they were correct, but rather because they did matches that were impossible.
You simply cannot match a bullet fired from a hammer-forged barrel such as the one used in a Glock pistol.
I will close with the biggest misunderstood science of them all — DNA. More specifically, touch DNA. This differs from DNA extracted from a source such as semen or blood.
This identification tool is incredible, unique and accurate. However, the issue is with its transference. This is particularly relevant to firearms. In lab tests conducted nationally, DNA was discovered only between 10 and 15 per cent of guns tested that they know were handled.
This becomes even less likely to detect if it is not carried in your waist.
So Jamaican gunmen would have less chances of detectability than Jamaican licensed firearm holders based on the fear of detection by the latter.
Now I imagine Jamaican judges and prosecutors know this, but do Jamaican juries know as well?
The use of DNA as an identification tool in rape cases is extremely useful.
However, the absence of DNA does not mean there was no rape. In fact, if a victim has consensual sex with someone and is raped by another in a time period that is prior to bathing, it is quite possible that the DNA detected is the first partner and not the second.
Then there is the perception that someone's DNA can look like someone else's because of improper preservation of a sample.
This is garbage and was the garbage that was sold in the O J Simpson case that resulted in his acquittal.
So where do we go from here?
Well science can only be useful if it is understood. Make it part of the rules that the limitations of the tests are outlined in court as part of the presentation of the evidence.
The potential tragedy here is not only that we are freeing the guilty that may kill again and hurt again. It's that this misunderstanding of science may result one day in the conviction of an innocent man.