What They Are ^Fingerprints are the impressions (images) formed by the reproduction of the friction ridge patterns of the fingers, palms and soles of the human body when they come into contact with a smooth surface. These friction ridges first appear in the fourth month of gestation and remain unchanged throughout life, even after death and until decomposition of the body.
The fundamental properties of fingerprints are that they remain unchanged and unaltered under normal conditions, and that there is no possibility of the individual characteristic points being identical between two different persons, or even between different fingers of the same person. To date, and following numerous comparative studies and investigations, no identical fingerprints have been found to originate either from different persons or from different fingers of the same person.
Fingerprints are classified as:
Positive and negative;
Visible or patent, which can be distinguished with the naked eye; and
Latent or invisible, which are formed by perspiration containing various inorganic and organic compounds, such as salts, glucose, cholesterol and volatile fatty acids, which vary according to the person’s diet, living conditions, etc., and which are developed by means of magnetic and conventional powders, chemical substances and other technical methods.
The identification of two fingerprints is based on correlation through comparison of a sufficient number of individual characteristic points, considered in conjunction with their uniqueness and individuality.
Fields of Application ^
The scientific and technical use and comparison of fingerprints enables the reliable identification of any living or deceased person. In particular, it is the method by which we are led:
- To the identification of unknown perpetrators of a criminal act.
- To the confirmation of the identity of arrested persons.
- To the correlation of suspected persons with fingerprints found at the crime scene.
- To the identification of victims and missing persons.
- To the identification of persons who legitimately came into contact with the relevant place or object.
- To the identification of persons who provide false particulars or refuse to provide identity details.
- To the resolution or confirmation of identity disputes in cases of persons bearing the same name.
- To the identification of persons suffering from amnesia, deaf-mute persons and persons in a coma.
- To the identification of unknown bodies resulting from road traffic accidents, mass disasters and other causes.
- To the detection of the imprisonment of the wrong person and the prevention of the release of the wrong person.
Evidential Value ^
From a procedural standpoint, a fingerprint constitutes an indication, not proof, that the person to whom it belongs committed a criminal offence. It indicates either the person’s presence at the scene, when found on fixed (non-movable) objects, or contact with the movable objects on which it was found, and not the use of those objects, even where they were used as instruments in the commission of an offence. When fingerprints are found, the following must be considered in order to draw sound conclusions:
- The distinction between contact and use of an object.
- The exact location in the premises or on the object where the fingerprint was found.
- The justified presence at the scene, as well as the justified contact with the object in question.
- The coexistence of other indications on the fingerprint, such as blood, paint, oil, etc.
- The justified coexistence of other indications (such as those above) on the fingerprint.
- The coexistence of additional fingerprints, even if unsuitable for comparison.
- The procedure followed for detection, collection/copying, transport and use.
- Any other element arising from the actual circumstances of each case.
Conduct of Examinations
^ Drawing upon scientific and technical data and applying methods that are internationally recognised, scientifically documented and judicially admissible, we carry out:
- Marking the individual characteristic points and evaluating the characteristic points used for comparison.
- Evaluation of the place and position of discovery (movable or non-movable object).
- Evaluation of acquired characteristics interrupting the continuity of the friction ridges (permanent or healable injury).
- Evaluation of the procedure followed, namely the method and means of development, collection/copying, packaging, transport, storage, handling and use.
- Qualitative evaluation of fingerprint records.
- Qualitative evaluation of the recording of the latent fingerprint.
- Evaluation of factors capable of altering a fingerprint, such as cold, humidity, the surface on which it was deposited, etc.
- Evaluation of fingerprint authenticity.
- Evaluation of the type, category, classification and kind of fingerprint, as well as the area of the body from which it originates (finger, palm or sole print).
- Evaluation of the classification and filing of fingerprint records.
- Evaluation of finger determination, where applicable.
- Investigation of the legality of the fingerprinting procedure carried out.
- Evaluation of whether the person’s presence at the scene and contact with the object in question were justified.
- Evaluation of the coexistence of other indications in the fingerprint (e.g. blood, colouring substances, etc.).
- Evaluation of usable fingerprints according to the area where they were found and the prevailing conditions.
- Evaluation of identification or association, either between fingerprints or between fingerprints and persons.
- Evaluation of the finding of fingerprints unsuitable for comparison.
- Evaluation where no fingerprints were found.
- Interpretation of the evidential value of the fingerprints found.
On-site Examination – Evaluation – Utilisation
^ In addition, we carry out:
- On-site examination at scenes of various criminal acts or other incidents, as well as inspection of relevant objects, in order to evaluate the areas examined and the areas where fingerprints or other traces were found and collected.
- Evaluation of Laboratory Examination Reports, Expert Reports and Opinions issued by State and other Laboratories or Specialistsin cases relating to fingerprints.
- Utilisation of evidence requiring further examination, by identifying forensic points for additional analysis, documentation and presentation, and by identifying points that are capable of laboratory examination or exploitation but for which no corresponding request was made.
Indicative questions that may be raised, depending on the case under examination
^ - What is the evidential value of the fingerprint?
- Under what conditions may the presence of a fingerprint be justified?
- Which characteristic points indicate the identification of a fingerprint?
- How is the location where the fingerprint in question was found (place, position, object) evaluated?
- How is the methodology used to search for, lift, record and examine the fingerprint in question evaluated?
- Which points or elements are used to assess the authenticity of a fingerprint?
- What does it mean that no usable fingerprints were found?
- What does it mean that no fingerprints at all were found?
- How is the association of fingerprints evaluated?
