Fingerprints have been one of the most successful methods for absolute identification. Along with our DNA, our fingerprints belong solely to us. No two people have the same fingerprints, including identical twins. We carry our fingerprints with us everywhere we go, we leave them on surfaces that we touch. They are easily collected and analyzed, and there is a national fingerprint database (Automatic Fingerprint Identification System or AFIS) that allows law enforcement to compare prints collected from widespread locations. Fingerprinting has a long history. It was first used in a criminal case in Argentina in 1892. Since then it has found its way into courtroom after courtroom and has helped solve innumerable criminal cases.
Why do we have fingerprints? Are they just for identification or do they serve some purpose? Actually, they’re critical to many of the things that we do on a day-to-day basis. Here’s an experiment for you: smear butter on your fingers and then try to pick up a glass full of water. Not easy to do and will likely create one heckuva mess. Our fingerprints give us traction and grip and allow us to hold on to things. In technical terms, they are called friction ridges.
But, can our prints disappear? Or be altered to deter identification?
Certain cancer drugs, like capecitabine (trade name Xeloda), can eradicate fingerprints. When someone takes this medication for several years, it can rarely cause what is called hand-foot syndrome. This is a drug-induced inflammatory process that involves the hands and feet. The skin becomes inflamed, and then swells, blisters, cracks, and bleeds. Over time, this recurrent damage to the skin can result in a complete loss of fingerprints or at least a significant attenuation of them so that they are difficult to detect. This has led to problems for some cancer patients when trying to get through airports around the world.
Friction ridges can also be worn down by those who work with abrasive objects, such as bricklayers. Aging can also “smooth out” our prints.
Could you use this in a novel as a way for your bad guy to eradicate his fingerprints? Maybe, but not easy. Let’s say your villain decides to eradicate his prints with medications. For someone to develop hand-foot syndrome they must be on the medication for a number of years, which makes it impractical. Plus, this is a chemotherapeutic agent, and as such, possesses numerous other side effects. Things like fever, chills, diarrhea, nausea, abdominal pain, weight loss, and stomatitis (inflammation and erosions of the mouth and throat). Wouldn’t that make for a pleasant villain? Also, hand-foot syndrome is rare so there is no guarantee that your villain, even if he did take the drug for a couple of years, would lose his fingerprints. In fact, the odds are against him.
For years, criminals have attempted to remove their fingerprints by various methods. The infamous John Dillinger used acid while others have used fire, hot pokers, and all kinds of cutting instruments to try to cut away or alter their fingerprints in such a way that they cannot be identified. Actually, the exact opposite is the case. When someone adds cuts and scrapes and burns to the pads of their finger, they are actually adding even more unique identification marks. It is similar to a car tire that has picked up cuts and scrapes from the road, or rocks or bits of glass embedded into its treads. If a tire impression found at a crime scene reveals these types of wear patterns and foreign bodies and if a car is then located whose tire exactly matches the pattern, then that is very strong evidence that it was this tire that laid down the crime scene impression and that no other tire could have had the same constellation of wear patterns and foreign bodies. In other words, this only makes the tire more identifiable. The same is true with fingerprints. If an individual has scars on his prints that exactly match those of prints left at the crime scene, then he has done the police a favor by adding these very unique and individualizing characteristics to his fingerprints.
Here are a couple of articles that might prove interesting:
Scientific American: https://www.scientificamerican.com/article/lose-your-fingerprints/
The History of Fingerprinting: http://www.onin.com/fp/fphistory.html