Fingerprints in forensics, are formed when residue from the ridged skin of the fingers is transferred onto a surface, leaving behind an impression.
Fingerprints are often made of sweat and colourless contaminating materials such as soap, moisturiser and grease. These fingerprints are described as “latent” since they are invisible to the naked eye, which means that locating them at a crime scene can be difficult.
Fingerprints hold a lot more information than one might realise. Several studies carried out on fingerprints has revealed a lot of information about them which crime investigators are exploiting to help unravel crime mysteries. These are some facts about fingerprints you should know.
1. Fingerprints don’t just provide a pattern or impression with which to identify people. They can also contain DNA.
2. Not until recently forensic scientists usually have to choose between one or the other, as recovering DNA can mean destroying the fingerprint and vice versa. But they could not collect both types of evidence at once.
3. No crime scene is contamination free. Crime scenes are not sterile environments, therefore its possible for latent fingermarks to be contaminated with DNA from the same person or from different people.
4. It is not all fingerprints left at crime scenes that are valuable as evidence. Some are simply smudges or are deposited onto surfaces that affect their quality. There are surfaces that absorb fingerprints which makes it difficult for recovery.
5. A recent discovery shows that both DNA and fingerprints can be recovered from fingermarks impression. The new method involves applying a soft, low-adhesive gel material to the surface for a couple of seconds to recover any DNA-containing material while leaving any fingerprints intact.
6. A chemical agent which makes fingerprints glow for months gives clearer image resolutions. Scientists say that a clean resolution of fingerprint furrows and ridges can provide information about a patient’s metabolism.
7. It’s possible to determine how long a fingerprint impression has been since the last contact from individual. Hence, the age of fingerprints can be ascertained.
8. No two individuals can have the same fingerprint impression, not even identical twins
9. Identical twins have the same DNA profile but have different fingerprint impressions.
10. It is possible to detect cocaine, heroin and morphine use from a single fingerprint.
11. One can tell the fingerprints of drug users and non drug users apart. This because, an actual drug user will deposit up to 100 times more in their fingerprints.
12. In addition, drugs can still be detected even after the user washes their hands, because the substances are continually excreted after use.
13. Chemical analysis of fingerprints can reveal a glimpse of a person’s lifestyle and environment, such as job, eating habits or medical challenges. This could help identify suspects in criminal investigations
14. Studies have shown that prescription medications can be detected in fingerprints, and these traces varnish when a patient stops taking their medication.