Lip prints, like fingerprints are unique to an individual and can be easily recorded. Identification plays a major role in any crime investigation.
The pattern of wrinkles on the lips has individual characteristics like fingerprints.
Cheiloscopy is a forensic investigation technique that deals with identification of humans based on lips traces.
Use Of Lip Prints In Crime Detection
Lip prints have the same value as Dactyloscopic traces.
Just like finger print and teeth, lip print can be used as tool for identification.
Lip prints are unique and do not change during life of a person.
They can be most frequently seen during murders, rapes and burglaries.
Traces with clear lines and individual elements enable individual identification of human beings.
In their character they are similar to other chemical and biological traces.
What Is Vermillion Zone?
The lips are the junction between the skin of the face which is Para keratinized stratified squamous epithelium and the mucosa of the oral cavity which is moist non-keratinized to Para keratinized stratified squamous epithelium.
Between these two areas lies a transitional zone of reddish tissue known as the vermillion zone of the lip.
It is this vermillion zone which is commonly denoted as ‘lips’ in forensic identification procedures.
- The biological phenomenon of systems of furrows on the red part of human lips was first noted by anthropologists R. Fischer in 1902.
- In 1932, one of the France′s greatest criminologist Edmond Locard, recommended the use of lip print for identification of a person.
- The idea of using lip print for identification was first suggested by Le Moyne Snyder in the year 1950. He introduced a case in which lip prints helped the crime scientist in an unusual way.
- Dr. Martins Santos in 1960 proposed that these lip characteristics could be used in personal identification and devised a simple system for classifying lip prints.
- In 1967, Suzuki made a detail investigation of the measurement of lips, the use and the colour of rouge and method of its extraction to obtain useful data for forensic application.
- Later in 1971 Suzuki and Tsuchihashi, conducted a study and they devised their own classification.
- Mc Donell in 1972 conducted a study on lip prints between two identical twins and reported that two identical twins seemed to be indistinguishable by every other means but they had different lip prints.
- Cottone in 1981, reported in his book Outline of Forensic Dentistry, that Cheiloscopy is one of the special techniques used for personal identification.
- In 1990, Kasprzak conducted research for the period of 5 years on 1500 persons to elaborate the practical use of lip prints.
Anatomy & Morphology of Lips
Lip of human being consists of 2 parts
1.) Upper Lip
2.) Lower Lip
Both these upper & lower lip are divided into six different regions, which are as follows-
Other features of Lips
Following features are also present in lips which is use for individualization & comparison, which are as follows:
In 1967 Santos was the first person to classify lip grooves. He divided them in to four types namely:
- Straight line
- Curved line
- Angled line
- Sine-shaped line
Suzuki and Tsuchihashi, in 1970, devised a classification method of lip prints as follows:
- Type I : A clear-cut groove running vertically across the lip.
- Type I′ : Partial-length groove of Type I.
- Type II : A Branched groove.
It include branch grooves across the whole lips.
- Type III : An intersected groove.
It include grooves which are intersecting each other.
- Type IV : A Reticular pattern
In this type lips contains rectangular grooves.
- Type V : Other patterns.
Grooves which about fall in any of the above four categories.
Another type of Classification
Another Four types are also used to classified Lip Prints
Lip Groove Types
A – Complete Vertical; B – Incomplete Vertical;
C – Complete Bifurcated; D – Incomplete Bifurcated;
E – Complete Branched; F – Incomplete Branched;
G – Reticular Pattern; H – Cross Form;
I – Horizontal / Complete Horizontal; J – Horizontal With Other Forms.
Forms Of Lip Prints Found On Crime Scene
These 3 types of Lip Prints can be found at the scene of crime. Lip prints are available particularly in the following forms-
1.) Visible Lip Prints – These are the Lip Prints which are visible to the unaided eye and it do not need any further development for its visualization.
2.) Latent or Hidden Lip prints – These are the Lip Prints which are not visible to human eye. It requires further development processes for its visualization.
3.) 3-D or Plastic Lip Prints – These are the Lip Prints which are found on soft, gel like surface (wax or butter). They are visible to unaided eye but sometimes need develop processing for photography.
How To Search Lip Prints On Crime Scene
- The search for possible Lip Prints needs a systematic and narrowly approach to the suspected areas.
- A magnifying lens is useful to locate and judge the quality of the Lip Prints.
- Traces of lips should be looked for on cutlery and crockery items, on the window or door glass and on photograph or letters. Lip print may also appear on side by side with tooth marks on food products. In practice, lip prints have also seen in the windows, painting, doors, plastic bags and cigarette ends.
- Observation under white light may reveal latent Lip Prints that can be photographed without any further treatment.
- Lip Prints can frequently be seen by holding the flashlight at low angles so that the surface is observed under oblique lighting.
- In some cases, latent print can often be detected using episcope coaxial illumination. The print is, therefore, visible as dark ridges against a light background.
The process is concerned with recognition, examination, identification, individualization, and evaluation.
Development of Lip prints
1.} Powder Method
2.} Chemical Method
3.} X-Ray Method
1.} Powder Method
Following methods are used for developing Lip Prints:-
A powder technique is usually used to identify latent prints on nonporous surfaces such as glass, marble, metal, plastic, and finished wood.
When powder is distributed on the surface, it adheres to the residue deposited from the finger’s touch, allowing investigators to find the print.
- Following Powder Method Can Be Used To Develop Lip Print-
- Aluminum Powder Method
- Magnetic Powder Method
- Plumb Carbonate Powder (White Powder)
2.} Chemical Methods
Crime Scene Investigators Often Use Chemical Methods To Locate The Print Such As;
- Iodine Fuming [must be photographed quickly because Print fades quickly after the fuming takes place],
- Silver Nitrate (Agno3) [works well on impressions left in cardboard and paper-like surfaces],
- Ninhydrin, [reacts with the oils in the print’s residue to create a bluish print],
- Lysochrome Dyes (Sudan 3 Dye And Oil Red ‘O’ Dye/ Red ‘O’ Dye),
- Small Particle Reagent (SPR).
When one of these chemicals comes into contact with the chemicals present in the Lip Prints residue (natural oils, fats), the print become visual.
3.} X-Ray Method
- Lead powder distributed on suspected area with the help of brush.
- Dusted area should X-Rayed and then photographic film of X-Ray should treat with required chemicals.
Development of lip prints on Multi colored surface
Following 3 methods can be used to develop lip prints on multicolored surface –
- Sudan Black Reagent – it can applied directly to the print.
- Yellow Fluorescent Powder (Illumination through UV light)
- Nile Red Reagent
Lifting of Lip Prints
There Are 2 Methods Are Applied For Lifting Of Lip Prints-
- Photographic Method – The developed prints should always be photographed by using a fixed focus camera or variable zoom photographic camera with the help of measuring.
- Transparent Tape Method – Powder dusted lip prints can be lifted with the help of transparent tape from a liquid and hard surface.
Collection of Lip Prints from Suspect
- Lip prints can be recorded in a number of ways.
- Photographing the suspect′s lips.
- Applying lipstick, lip rouge, or other suitable transfer mediums to the lips and then having the individual press his or her lips to a piece of paper or cellophane tape or similar surface.
- By having the subject impress his or her lips (without lipstick or other recording medium) against a suitable surface and then processing these prints with either conventional finger print developing powder or with a magna brush and magnetic powder.
- On a non-porous flat surface such as a mirror they can be photographed, enlarged and overlay tracings made of the grooves.
Examination and Comparison
Generally two prints are required for comparison :
- A lip print recorded from the Scene Of Crime (SoC);and
- A lip print which has been taken from suspect.
Both compared on the basis of individual characteristics of Lip Prints.
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