Fingerprint Types Commonly Fou...

In criminal investigations fingerprints are one of the oldest and most common types of physical evidence found at a crime scene.

One of the primary goals of the investigation deals with identification. Whether the identification is that of an unknown victim or that of the perpetrator of a crime.

The ridge detail developed and recovered at a crime scene and later identified by a fingerprint examiner becomes an investigative lead for the detectives assigned to the investigation.

The friction ridge feature of the hands and feet is simply characterized as a fingerprint. Friction ridges have two primary functions. Firstly, they enable us to grip and cling onto a variety of objects and secondly they are used as a form of person identification in forensics.

Fingerprints and The Crime Scene Investigator

The person who is in charge of processing the crime scene and recovering the latent impressions varies by department and agency across the country.

The purpose of a crime scene investigator or evidence recovery technician is to identify and collect friction ridge detail that may have been deposited on a variety of surfaces at a crime scene.

The crime scene investigator/technician must be familiar with the many types of ridge detail that could be deposited on the scene, as well as the surfaces that would preserve the detail and the means for recovering such deposits. Today's greatest technological difficulty is keeping up with the ever-changing surface materials.

Most Common Types of Fingerprints Found at The Crime Scene

At a crime scene, there are three primary sorts of impressions that can be deposited, detected, developed if necessary, and collected.

Latent Fingerprints

The skin has deposits of oil and perspiration that normally coat the surface.

When the hand touches the surface, some of the moisture is transferred from the hand to the object, leaving an impression of the friction ridge detail. These are referred to as latent impressions.

On most surfaces the latent impressions are not readily visible. The word latent is defined as not visible. That does not mean that it is actually invisible.

Using available or oblique lighting on most surfaces will reveal the impression. The impression must be enhanced or developed to be seen fully and collected. 

The latent fingerprints are also called invisible prints, a more common phrase used by most people due to their nature as they are not visible to the naked eye without any developmental processing.

Patent Fingerprints

The transfer of a foreign material coating the skin of the fingers results in a patent imprint.

Paint, tar, grease, blood, or ink, are examples of foreign materials. After the ink has been applied, it becomes a foreign substance that coats the individual's hands.

A card is utilized as a transfer medium, becoming the object that is touched, and the patent impression is transferred.

The term "patent" refers to something that is visible. These impressions are frequently visible and do not require any treatment. They are simply photographed, and if necessary, the item on which they are deposited is also collected.

Plastic or Molded Fingerprints

When the hands, fingers, or feet are placed into a soft rubbery type substance that will hold the impression of the ridge detail, a plastic or moulded impression is formed.

A plastic or moulded impression would be put into the surface where a latent impression is deposited.

Clay, wet paint, blood, and tar are examples of materials where a plastic impression could be left.

Impression made of plastic or moulded material is evident and usually does not require any treatment. They are merely photographed, and the object is collected if necessary, with the possibility of being caste.