CHEILOSCOPY

Definition

Cheiloscopy is a forensic investigation technique that deals with identification of humans based on lips traces.

History

The biological phenomenon of systems of furrows on the red part of human lips was first noted by anthropologists. R. Fischer was the first to describe it in 1902. Until 1950, however, anthropology merely mentioned the existence of the furrows without suggesting a practical use for the phenomenon. Since 1950 the Japanese have carried out extensive research in the matter. In the period 1968-1971 two Japanese scientists, Y. Tsuchihashi and T. Suzuki examined 1364 persons at the Department of Forensic Odontology at Tokyo University. Based upon that research it was established that the arrangement of lines on the red part of human lips is individual and unique for each human being. This statement led to the conclusion that there is the possibility of using the arrangement of furrows (on a trace, in a linear form) on lips for the identification of a person. In further research the Japanese scientists examined the principles of the heredity of furrows on the red part of lips. It was in Hungary during 1961 that the first research in Europe was carried out in the subject of lip prints. The examination started after lip traces had been found on a glass door at the scene of a murder. It was established later that the murderer pushed the door open with his head because his hands were covered in blood, leaving a trace of the red part of his lips on the glass. In the process of examination of the lip traces their usefulness for criminalistic identification was proven.
Cheiloscopic research was also carried out by specialists in anthropology, odontology, forensic medicine and forensic science, in Brasil, Iran, Hungary, France, Germany, Italy, United Kingdom, the Soviet Union and Czechoslovakia. The results of this research constitute the proof of lip-print individuality and also of its usefulness for criminalistic identification.
In Poland, the interest in lip prints started in 1966 when a lip print was revealed on window glass at the scene of a burglary. Research was carried out, and its results were comparable to those achieved in Japan and Hungary.
The research was only of preliminary character and did not allow for practical application of results as yet. There was a need to develop one cohesive cheiloscopy system, practicable in forensic cheiloscopy.
A project aiming at that objective was launched in 1982, in the Forensic Institute of Warsaw University Criminal Law Department, in cooperation with the former Forensic Institute of Militia in Warsaw. The material for study was collected in the former Military Training Center at Minsk Mazowiecki. Lip prints were collected from 1500 persons (including 107 women), coming from various locations around the country. The age of the volunteers varied from 5 to 60 years. Altogether more than 7000 traces of the red part of the lips were examined. As a result of the examination the individuality of lines in the red part of lips and their unchangeability within the limits practicable for identification was proven. The examination determined methods for revealing and securing the traces of the lips, methods of acquiring the comparative material, and, more importantly, detailed methods of cheiloscopic expertise. The possibilities of registration of traces of the red part of lips were also examined, and a file comprising 1500 individuals was organized on a laboratory scale.
Since 1985, in Poland, the methods of finding and recovery of lip traces, recovering comparative material, and the techniques employed to carry out that expertise have been introduced into casework of the Fingerprint Department, of the Central Forensic Laboratory of Police in Warsaw. During the years 1985-1997, cheiloscopic techniques have been used in 85 cases, including 65 burglary cases, 15 cases of homicide, and five cases of assault. In 34 cases the identification was positive, which means that cheilo-scopic techniques were equal in value to other types of forensic evidence. It has also been included in evidence for presentation in court.

The Subject and Scope of Cheiloscopy

It is not easy to place the lip prints in the general system of traces. A lip print may be revealed as a stratified surface trace with visible elements of lines (furrows). In this case a trace has the shape of a print -the individuality of its properties make it possible to individually identify a human being. In the case when the lines are not clear (only the shape of the lips is printed), individual identification of a human being based on this trace is extremely difficult (unless the trace contains more individual characteristics, e.g. scars), and often identification ends with group identification. In these cases it is possible to examine the substance which constitutes the trace e.g. saliva, as a biological trace. The potential for DNA typing from the lip print is evidentially here. However, this process has so far not been attempted. If the lips are covered with remains of food or cosmetics and the lines are printed unclearly, the trace will have the shape of a stain, and can be subjected to chemical examination, in order to determine the substance covering the lips. The value of such a trace will depend on its type. Traces with clear lines and individual elements enable individual identification of a human being. In this sense lip prints have the same value as dactyloscopic (fingerprint) traces. In the case of traces in the shape of stains the identification examination terminates with group identification, in their character they are similar to other chemical and biological traces (including DNA identification).
Apart from identifying and evidential use, lip prints may also be used in detection work, being the source of tactical and criminalistic information. A lip print at the scene of a crime can be a basis for conclusions as to the character of the event, the number of the people involved, sexes, cosmetics used, habits, occupational traits, and the pathological changes of lips themselves.

The Use of Lip Prints in Crime Detection

A trace of this kind can only be revealed at the point of direct, physical contact of the perpetrator’s lips with an object at the scene of a crime. This trace should be looked for on cutlery and crockery items, particularly if a meal was eaten at the scene of a crime.
In practice, lip prints have also been revealed on the surface of windows, paintings, doors, plastic bags and cigarette ends.
Finding and recovery of lip traces is not difficult. The techniques used in fingerprinting are very good for the purpose. The easiest method makes use of fingerprint powders and fixing on foil. Aquaprint and cyanoacrylamide may also be applied.
The taking of control prints from the suspect (comparative material) is also not difficult. The method of obtaining the traces was the following. The examined person covered the mouth with a thin layer of skin care cream (e.g. Nivea). After about 3 minutes, a strip of paper 120 mm long and 45 mm wide mounted on a specially profiled roller (made from fingerprinting roller) was lightly pressed to the lips. The impression was subsequently visualized with the use of ferromagnetic powder used in developing latent fingerprints, and then fixed on transparent foil.
In the course of research a classification of patterns of the lines of the red part of lips was made. As the basis for classification, the middle part of the lower lip, 10 mm wide, was taken. This fragment is almost always visible in the trace. The determination of the pattern depends on the numerical superiority of properties of the lines on the fragment (Fig. 1). If the lines prevail, the pattern is described as linear, ‘L’. If the bifurcation is dominant, it is called bifurcate, ‘R’. If the lines cross, the pattern is dubbed reticular, ‘S’. In the case when no superiority can be established, the pattern is named undetermined, ‘N’. This classification has been proven in practice.

Figure 1 Types of patterns on the red parts of lips.
The next step in the identification is establishing individual features of the pattern of the lines. The discussed study resulted in the first catalogue of 23 types of individual features. The types of features were differentiated as a result of microscopic examination of lip prints, collected from 1500 individuals. The types of features were listed separately (Table 1) but in practice the features occur in combinations of two or more. An element of a feature, or the whole feature may appear as a part of another feature,which is the main difference between properties of system of furrows on lips and those of fingerprint lines (Fig. 2).

Table 1 Individual features of line pattern on red part of lips

In order to examine carefully the number of individual features appearing on the trace, their distribution and frequency of occurrence, 100 traces were chosen at random from each kind of pattern. A total of 400 lip prints were analyzed in detail. The examination required the observation of the trace and the count of noticeable features identical with those 23 distinguished individual features in the catalogue. In the 400 lip prints examined 456 215 individual properties were found which gives an average of 1145.5 individual features per trace. Such a high number of individual properties appearing on a lip print opens for cheiloscopy new previously unperceived venues in the scope of personal identification.
The research discussed above has led to the creation of a set of useful practical methods of lip print analysis. There is already a ‘protocol’ for carrying out a cheiloscopic examination:
1. The method of determining common features;
2. The method of photographic montage;
3. The contour method.
The determining of common properties is the most basic identification method. The essential part of this method is the thesis that in order to establish identity between evidential and comparative material one should determine the common features, including individual features from the catalogue of 23 types of features (Table 1). According to the theory of combinations, using the same principles as in fingerprint analysis, in order to established identity of an evidential trace with a comparative trace, one should determine seven individual features for Poland and nine features for the whole world. However in Polish forensic practice, usually 15-20 common features are distinguished. The photographic montage method and the contour method supplement and support the method of establishing common properties. In the method of a photographic montage, a fragment of the photograph of a comparative trace is fitted to a photograph of an evidential trace and the conformability of individual properties is examined. In the contour method, contours of the most characteristic arrangements of lines, on the red part of the lips are transferred onto transparent foil and are then compared with the lines in the photograph of evidential and comparative traces.

Figure 2 Lip print from the scene of a burglary.
The practical use of lip prints in detection work shows that the trace of this kind carries a huge amount of precious information which can be used in the reconstruction of the event, establishing versions and checking them and identifying suspects.
Full utilization of lip prints depends to a high degree on the skill of members of the law enforcement agencies. The problems involved in cheiloscopy are relatively little known and thus, so far, lip prints have been used only occasionally, despite their frequent occurrence on the scene of the crime.