An Overview On Forensic Sciences And Criminology
There is urgent and widespread need for the application of forensic science in criminal investigation. The present day picture of crime investigation and prosecution of criminals, is a sad story. A large percentage of the murder trials, ultimately, end in acquittal. It is estimated that the prosecution agency spends on an average over Rs.10,000.00 per trial. Thus, not only a dangerous criminal goes scotfree but huge amount of public money is also wasted. These frequent acquittals also embolden the criminals.
Forensic Science in criminal investigations and trials is mainly concerned with materials and indirectly through materials with men, places and time. Among men, the investigating officer is the most important person. Infact ,it is he whose work determines the success or failure of the application of forensic science in the processing of a criminal case. If he fails to collect the relevant evidence, allows the exhibits to be contaminated or does not provide correct samples for comparison, the findings of a forensic scientist will be useless.
Forensic Science embraces all branches of science and applies them to the purpose of law. Originally all the techniques were borrowed from various scientific disciplines like chemistry , medicine, surgerybiology, photography. But in the past few years it has developed its own branches which are more or less exclusive domains of forensic science. More recently significant advances have been made in serology, voice analysis, odour analysis and in studies relating to nose prints and ear patterns.
The need for the application of science in criminal investigation has arisen from the following factors:
The society is undergoing drastic social changes at a very rapid pace. India has changed from a colonial subject race to a democratic republic. Sizeable industrial complex has sprung up. The transport facilities have been revolutionized. There is a growing shift from a rural society to an urban one. These changes have made the old techniques of criminal investigation obsolete. In the British days the police was so much feared that once it had laid its hands upon an individual, he would ‘confess’ to any crime, he may not have even known. The fear is vanishing now. The use of ‘third degree’ techniques used in those days does not find favour with the new generation of police officers and judges.
The quick means of transport and high density of population in cities have facilitated the commission of crimes. The criminal can hide himself in a corner of a city or move away to thousands of miles in a few hours. He, thus often escapes apprehension and prosecution.
The technical knowledge of an average man has increased tremendously in recent years. The crime techniques are getting refined. The investigating officer, therefore, needs modern methods to combat the modern criminal.
Wide field: The field of activities of the criminal is widening at a terrific rate. Formely, the criminals were usually local, now we find that national or international criminal is a common phenomenon. Smuggling,drug trafficking ,financial frauds and forgeries offer fertile and ever expanding fields.
Better Evidence: The physical evidence evaluated by an expert is objective. If a fingerprint is found at the scene of crime, it can belong to only one person. If this person happens to be be the suspect, he must account for its presence at the scene. Likewise, if a bullet is recovered from a dead body, it can be attributed to only one firearm. If this firearm happens to be that of the accused , he must account account for its involvement in the crime. Such evidence is always verifiable.
Forensic science provides answer to the following three questions:
1. Has a crime been committed?
Consider the case of recovery of a dead body. Death could be natural accidental or homicidal. Forensic Science by ascertaining the nature of death, establishes the existence or absence of corpus delicti.
2. How and when was the crime committed?
The examination of the ‘corpus delicti’ reveals the way of the crime was committed and possibly the time when it was committed.
3. Who committed the crime?
Forensic science establishes the identity of the culprit through personal clues like fingerprints, footprints, blood drops or hair. It links the criminal with the crime through objects left by him at the scene with the victim or carried from the scene and the victim.
On the other hand, if the clues recovered do not link the accused with the victim or the scene of occurrence, the innocence of the accused is established. Forensic science, thus, helps the innocent.
The application of Forensic Science in the investigation of crime can be effective only if the investigating officer knows:
1. The nature of physical evidence to be collected.
2. Where it is found.
3. How it is collected and packed.
4. What standard samples for comparison purposes are necessary.
5. How much sample is required.
6. How the sampling is done.
7. How the evidence will link the crime with the criminal and to what extend his labours will be rewarded by the laboratory results.
This is possible if the investigating officer is given a thorough grounding in the above aspects. He needs both theoretical and practical training.
All police training institutions have courses in scientific aids, but the syllabi and the teaching standards are far from satisfactory. Periodical attachment of investigating officers to the departmental forensic science laboratories can go a long way in inculcating the scientific spirit.
Ignorance about the value of evidence sometimes causes a lot of disappointment to an investigating officer. For example, hair are recovered in quite a few cases. Evaluation of hair does not lead to positive identification of the source of hair. It is not possible at the present stage of development of the science. They would not be disappointed , if they know the limitations.
The laws and principles of all the natural sciences are the bases of forensic science. In addition,it has developed its own principles.
Law of individuality- Every object, natural or man-made, has an individuality which is not duplicated in any other object.
This principle, at first sight appears to be contrary to common beliefs and observations. The grains of sand or common salt , seeds of plants or twins look exactly alike. Likewise, man-made objects: coins of the same denomination made in the same mint,currency notes printed with the same printing blocks one after the other (excluding serial number) and typewriters of the same make,model and batch appear to be indistinguishable. Yet the individuality is always there. It is due to small flaws in the materials, in the arrangement of the crystals , imperfect stamping or due to inclusions of some extraneous matter.
The individuality has been verified in certain fields. The most extensive work has been carried out in finger prints. Millions of prints have been checked but no two fingerprints, even from two fingers of the same person have ever been found to be identical.
The law of individuality is of fundamental importance in forensic science. Anything and everything involved in a crime, has an individuality. If the sane is established , it connects the crime and the criminal.
Principle of exchange- ‘Contract exchanges traces’ is the principle of exchange. It was first enunciated by the French scientist, Edmond Locard.
According to the principal, when a criminal or his instruments of crime come in contact with the victim or the objects surrounding him, they leave traces. Likewise, the criminal or his instruments pick up traces from the same contact. Thus, a mutual exchange of traces like takes place between the criminal, the victim and the objects involved in the crime If these traces are identified to the original source, viz., the criminal or his instrument (or vice versa), they establish the contact and pin the crime on to the criminal. The principal of exchange is aptly demonstrated in hit and run cases and in offences against person.
The basic requirement of the principle is the correct answer to the question ‘ What are the places or objects with which the criminal or his tools actually came in contact?’ If the investigating officer is able to establish the points of contact , he is likely to reap a rich harvest of physical clues:
1. If a criminal enters the premises through a ventilator , he leaves his foot prints in dust on the sill.
2. If he breaks a window or a door, the jimmy leaves its marks on the wooden frame.
3. The burglar, who opens a safe by an explosive, leaves the area around and the clothes (including shoes ) covered with insulating material as well as some exploded and unexploded explosive materials.
The criminal is likely to leave and carry minute traces only. It is seldom that he dares or neglects to leave or carry gross objects or traces. On a thorough search, the inconspicuous traces will always be found in all types of crimes. The minute traces connect the crime and the criminal as effectively as the gross objects or traces.
Law of progressive change- ‘ Everything changes with the passage of time’. The rate of change varies tremendously with different objects. Its impact on forensic science is immense.
1. The criminal undergoes rapid changes. If he is not apprehended in time, he becomes unrecognizable except perhaps through his fingerprints, bone fractures or other characteristics of permanent( comparatively speaking ) nature which are not always available.
2. The scene of occurrence undergoes rapid changes. The weather, the vegetable growth, and the living beings (especially human-beings) make extensive changes in comparatively short periods. Longer the delay in examining the scene, greater will be the changes. After some time , the scene may become unrecognizable.
3. The objects involved in crime change gradually, the firearm barrels loosen , metal objects rust , the shoes suffer additional wear and tear and the tools acquire new surface patterns. In course of time the objects may loose all practical identity vis-à-vis a particular crime.
The principle, therefore, demands prompt action in all aspects of criminal investigation.
Principle of comparison- Only the like can be compared is the principle of comparison. It emphasizes the necessity of providing like samples and specimens for comparison with the questioned items:
1. In a murder case, a bullet is recovered from the deceased. The expert opines that the bullet has been fired from a firearm firing high velocity projectiles like a service rifle. It is futile to send shotguns ,pistols or revolvers as the possible suspect firearm.
2. A bunch of hair is recovered from the hands of a deceased. The expert opines that the hair belong to a Negroid person. Hair from persons of white races for comparison will not be of any use.
3. The questioned writing is found to have been writing with a ball pen. To send fountain pen as a likely instrument of writing is futile.
Once handwriting available on a photograph allegedly written on a wall was compared with the specimen written on a paper. It did not give worthwhile results.
A second set of specimens was obtained by writing on the same wall, at the same height and with the same instrument and then photographed . It allowed comparison. (CH)
Principle of analysis- The analysis can be no better than the sample analysed. Improper sampling and contamination render the best analysis useless. The principle emphasizes the necessity of correct sampling and correct packing for effective use of experts.
1. A criminal while running away from the scene if occurrence brushes against a painted surface. Some powdered particles of paint get deposited upon his clothes. The investigating officer scraps a few grams of paint from the same surface with a pen-knife and sends it as control sample. The result of the analysis shows that the two paints do not match. Why?
2. A small amount of dust is recovered from a small sticky patch of the shoe of a culprit. The investigating officer collects about two kilograms of soil from the scene packs it in tin and sends it as a control sample. The results of comparison are inconclusive. Why?
3. In a rape case, the investigating officer collects the clothes of the victim. The clothe carry both blood and semen stains. The investigating officer dries the clothes and packs them together and sends them through a railway parcel. He wants to know if the clothes carry semen stains , and if so, to which blood group does the secretor belong?
The expert establishes the existence of semen but fails to give its blood grouping; because he finds powdered blood sticking to semen stain.
Facts do not lie- ‘Facts do not lie, men can and do’ , hence the importance of circumstantial evidence vis-à-vis oral evidence. The oral testimony depends upon the power of observation , assimilation and reproduction of the witness. It is modified by the power of observation, assimilation and reproduction of the witness. It is modified by auto suggestion , external influence, suggestions, descriptions and opinions of others and rationality. Oral evidence , therefore , is coloured whereas factual evidence is free from these infirmities.
But ‘facts’ can also be created:
1. A person is killed in an accident firing. The relatives want to implicate their opponents. They procure an unlicensed firearm, fire a cartridge ,place at at the scene and plant the firaram on the opponent.
The police recovers the shell and the firearm. The shell is married to the firearm. The police prosecutes the person.
2. A person is in the armed forces. He is seen carrying out duty upto 1 A.M. in the unit. He slips through the guarded premises, goes about a hundred miles, and commits a murder, returns to his unit, enters into the guarded premises secretly and is present on his duty at
By circumstantial evidence he proves his presence in the unit throughout the night.
3. A threatens B with death. The next day B is found murdered. B had no other enemies except A. Police suspects A as the murderer. He is not found anywhere. He is declared a proclaimed offender. Soon afer ‘A’ appears before a magistrate and says he had gone on a pilgrimage. But checking at the allegedly visited places, his visits to the places are not established. He is arrested and prosecuted. In defence , he produces the jail record. He was behind the bars at the relevant time. He escapes sentence.
Law of probability- All identifications, definite or indefinite, are made , consciously or unconsciously,on the basis of probability.
‘ Probability’ is mostly misunderstood. If we say that according to probability a particular fingerprint has come from the given source, the defence counsels will make most of the word and plead that it is not a definite opinion. Consequently, it is not customary to talk of ‘probability’ or ‘probability figures’ in counts.
Probability is the mathematical concept. It determines the chances of occurrence of a particular event in a particular way out of a number of ways in which the event can take place or fail to take place with equal facility. If P represents probability N1 the number of ways in which the event can successfully occur(with equal facility) and N2 the number of ways in which it can fail (with equal facility), the probability of success is given by the formula:
P= N1/ N1 N2.
We have neglected other factors (sex, age and dress) and even without these additional factors , the identity of the deceased is established beyond a ‘ reasonable doubt’.
Tools and Techniques
The tools and techniques of forensic science are oriented to meet the following exacting demands in an analysis :
The instruments and techniques should be highly sensitive because the quantities of materials involved are extremely small, often in micro , sub micro or microscopic ranges. For example, a few milligrams of certain poisons are sufficient to kill a person. The quantity is distributed in whole body.
Paints, soils , dusts , inks and body fluids are often met with in micro quantities.
The number of cases requiring evaluation of clues is increasing everyday. The techniques and instruments should , therefore, be rapid. In classical examination of viscera and organs each item is subjected to lengthy process of extraction, purification, identification and estimation. The results are checked and cross checked for mistakes. Modern techniques may eliminate most of these steps.
The tools and techniques currently used in modern forensic science laboratories belong to both classical and modern categories.They are as follows:-
Ø Invisible rays
Ø Laser Techniques
Ø Mass Spectrometry
Ø X- Ray diffraction analysis.
Forensic Science And Criminal Prosecution
I. Scene of Occurrence
A scene of occurrence is the meeting place of the persons involved. The parties exchange traces with one another and with the scene, leave odds and ends and mark of tools, wearing apparels, means of transport , hands and feet. Thus the scene of occurrence provides a wealth of information which is useful to:
1. Establish corpus delicti
2. Provide link between the criminal , the victim and the scene of occurrence; and
3. Evaluate the pattern of events.
The scene is of great importance in almost all crimes except perhaps in cases of forgery where the utility is limited.
The examination of the scene needs planning , care and diligence. In many cases the success or failure of the investigation depends entirely upon the proper handling of the scene.
The scene of occurrence changes rapidly and cannot be preserved forever. Some of the evidence gets lost soon after the occurrence, the other evidence disappears, gets contaminated or altered with further passage of time.
The opportunity to examine the scene is available only once. If the same is not fully exploited the wealth of information is lost for ever.
1. Raghunandan v State. Of U.P., 1974 Cri. L. J. 453 (S.C)
In the above case both the trial court as well as the High Court had brushed aside the objection that the blood recovered from the place of occurrence was not sent for chemical examination. The failure of the police to send the blood for chemical examination is a serious case of murder , such as the one before us., is to be depreciated . In such a case the place of occurrence is often disputed.
2. Marachalil Chandra Tukaram Talekar v State of Gujrat. 1980 Cri. L.J.5 (Guj)
Identity of the scene:
It was argued with great vehemence in the High Court as well as in the court of sessions that there was trial of blood from the front door of the house of the vakil into the corridor rooms marked H and H-1 in the plan and that supported the defence theory that the deceased Kannan received the stab injuries not in or near the house in question but somewhere far away near the railway station. The High Court took the view that if Kannan had received the injuries somewhere outside the house it was impossible for him to have come into the room in view of the doctor’s evidence.
It was concluded on the material placed on the record that there could be no room for doubt that Kannan received the injuries in the room itself and not outside, and that he was carried out of the room while life was still lingering and therefore there would be dripping of the blood from the body during the course of transit as the injuries were very serious and vital arteries had been cut.
The identification of criminals through fingerprints was the first important break-through in the scientific investigation of crime. As usual, the judiciary and the public took some time to believe in the utility of fingerprints as a scientific aid. The same is now recognized throughout the world.
The importance of fingerprints in criminal investigation is immense, because they are:
Ridge pattern of each finger has an individuality. The patterns vary not only from one individual to another , but they are different in the same individual on each finger. Duplication of pattern has never been observed. Nor the same is expected.
The fingerprints of an individual do not change throughout his life. In fact, the ridges appear before birth. They start appearing during third or fourth month of pregnancy. They remain even after the death of the individual ever till the epidermal skin is destroyed by fire, putrefaction or is eaten by insects or other creatures.
In a murder case the body of the victim was partially burnt and buried. The same was discovered many days after the murder. The body was completely disfigured and could not be identified.
The investigating officer got removed the remaining skin pieces from the tips of the fingers through a doctor. He sent them to fingerprint bureau alongwith the one authentic print of the deceased available on his will. The bureau confirmed the identity of the deceased.
The digital skin pieces were recovered and sent to the finger print bureau. The fingerprints of the deceased tallied with the fingerprints of the convict , available in the records,
The permanence of fingerprints permits identification of an individual even after many years, if his finger print record is available. Many criminals have been identified through this medium after years of absconding.
All individuals and hence all criminals carry this medium of identification. The finger digits and palmar surface of the hands carry the friction ridges. The fingers have more intricate patterns. They allow easier individualization and classification.
A criminal uses his hands in the commission of crime. He leaves marks at the scene of occurrence or on the objects which come in contact in the commission of crime. There are fair chances of occurrence of fingerprints , therefore in all types of crime.
Successful forgery of fingerprints has not been reported so far. Near perfect forgeries have been attempted. It is possible that the advancement of science may bring the forgery still closer to perfection but complete success in the enterprise is extremely difficult ,if not impossible.
For all practical purposes it may be taken that it is not possible to forge a fingerprint. This is important because no person can deny his or her fingerprints. The identification through fingerprints is certain and infallible.
The scope for classification of fingerprints is large and yet the work is simple. Records of millions of persons can be classified and kept on nicrofilms. Computerisation of fingerprint record, and hence searches are becoming popular and is increasing the efficiency. A search can be made virtually in seconds with the help of these devices.
1. The question was raised before the sessions Judge as to whether a conviction can be based upon the unsupported testimony of a fingerprint expert. There is no rule of law on the point; it is merely a matter of caution whether a court will act on such unsupported evidence or not. The correct principle was defined by S.K. Ghose,J. in Hatendra Nath Sen v Emperor.
“ I do not think that it can be laid down as a rule of law that it is unsafe to base a conviction on the uncorroborated testimony of a fingerprint expert. The true rule seems to me to be one of caution that is to say, the court must not take the expert’s opinion for granted , but it must examine his evidence in order to satisfy itself that there can be no mistake and the responsibility is all the greater when there is no other evidence to corroborate the expert”
In Bazari Hajam v King Emperor(AIR 1922 Pat.73 :23 Cr. L.J 638) the question arose whether it will be safe to act on the uncorroborated testimony of the fingerprints and declare the guilt of the accused. On this point Bucknill,J., observed thus:
“ I think that apart from the fact that I should be rather sorry without any corroborative circumstances to convict a person of a serious crime solely and entirely upon similarity of thumb marks or finger prints, the very fact of the taking of a thumb-impression from an accused person for the purpose of possible manufacture of the evidence by which he could be incriminated is in itself sufficient to warrant one in setting aside the conviction upon the understanding and upon the assumption that such was not really a fair trial.”
The above view was disapproved of by Schwabe, C.J. in Public Prosecutor v Kandasami Thevan (AIR 1927 Mad. 696 :27 Cr. L. J 1251) although the point did not directly arise in the case as there were thumb-impressions of the accused in evidence other than that taken by the judge in court for comparison with the thumb-impressions in the document alleged to have been forged.
III. Track Marks
The culprit approaches, stays and then leaves the scene of occurrence. He leaves track marks on and around the place in the form of prints and impressions( collectively called ‘marks’) of feet, shoes, tyres, hoofs and the like. The evidence often connects the criminal with the crime conclusively. It should, therefore be properly understood ,collected, evaluated and presented in the courts.
The track marks establish not only the presence of the culprit at the scene of crime but also give the number of participants. The evidence is helpful in tracking down the criminals to their houses or hide-outs, especially in India where most of the people live in rural areas. The roads in the country side are not metalled. Besides, the criminal, ordinarily, follows untrodden routes ; fields ,garden and stream beds. He leaves track marks on routes used before and after the commission of the crime.
The nature of the vehicle used in the commission of crime wether it is a cycle , scooter, car, bus, truck, tractor, rickshaw, bullock cart or a buggie can be ascertained. It is sometimes possible to identify the individual vehicle also.In some cases animals are involved in crimes sometimes. For example , a horse or a camel may be used for transport ; a cow , a buffalo or a bullock may be stolen or a dog or a tamed wild best , like a snake or a tiger may be used to destroy or kill a human-being or a domestic animal. The type of the animal or the beast can be found out from the track marks.
Foot Wear marks include the marks of shoes , sandals , chappals , socks and the like. The footwear may be factory- made or hand made.
Rejecting the contention that the study of footprints is not a science in Din Muhammad v Emperor , Central Provinces Police Gazette dated 27th May , 1914 pp. 125-130, the court of the Judicial Commissioner at Nagpur (H.J. Stanyon and H.F. Hallifax, A.J. Cs ) as far back as in 1914 held:
“The knowledge of footprints has similarly been systematized and pursued by trackers , mainly uncivilized and ignorant people an all other respects, all over the world . The matter is therefore undoubtedly a science and the opinion of a person specially skilled in it is a relevant fact, under Sec-45 of the Evidence Act “
In Re Paramban Manmmadhu, which is a bench decision of that court, delievered by Horwill, J (Supra) the learned judge held that opinion of a foot print expert is not admissible as evidence.
In the case of Pritam Singh v State of Punjab (AIR 1956 S.C. 415) there is an observation to the effect that the science of identification by footprints is a rudimentary science and much reliance cannot be placed on the result of such identification.
Poisons are frequently involved in homicidal accidental or suicidal deaths. They are sometimes used to destroy animals and plants. The detection of poisons and their identification is an important aspect of forensic science.
The investigation of cases of poisoning is one of the most difficult tasks. The quantity of a poison required to kill a victim is extremely small in some cases. For example , the fatal dose of nicotine is about 50 milligrams.
The investigation is further complicated by the variety of poisons available. The ever-increasing number of synthetic drugs which are used as poisons is further adding to the complications. Some drugs are very close to one another in their chemical and physiological behaviours. Their identification requires the most fined analytical techniques.
Body materials in which the poisons are found,is a complex mixture of organic , inorganic and biological substances. They interfere in the isolation , detection and estimation of the poisons. In fact the most difficult task of a toxicologist is to isolate the poison in pure form. Once it is done, it is comparatively easier to identify and estimate the quantity.
An analysis of some of the poisons which can prove detrimental is as follows :
Name of the Poison
1.0 to 2.0g of root
1 to 5 hours
250 to 500 ml
A few hours
0.13 to 0.2g
Half to 2 days
Within 24 hours
A few hours to few days
One day to several days.
A few minutes.
4 to 16g
A few minutes to a few hours
A few minutes to several days
A few minutes to several weeks.
Within a day’
1. The essential ingredients in a case of poisoning are no longer in doubt. The matter is concluded by a series of Supreme Court decisions. In Anant Chintaman Lagu v State of Bombay (AIR. 1960 S.C. 500), their lordships pronounced that the prosecution establish three propositions in a case of poisoning: i) Death took place by poisoning ; ii) Accused had the poison in his possession; and iii) Accused had the opportunity to administer poison to the deceased.
2. In Emperor v Shetya Timma( AIR 1926 Bom. 518) ,the death was caused by Dhatura poisoning. After review of conflicting decisions on the point, their lordships held that where the accused administered Dhatura poison to five men in order to facilitate commission of robbery and in consequence thereof three men died , the accused must be presumed to have knowledge that their act was so dangerous that it was likely to set aside. The same view was taken in Emperor v Chattarpal( AIR 1930 Oudh 502) .
Forensic Science And Sexual Offences
Serious common sexual offences are:
· Unnatural offences.
Some minor sexual offences are:
4. Voyeurism-‘Peeping Tom’
Certain sexual aberrations are:
In all the above cases Forensic Science play a major role in understanding the nature and gravity of the concerned crime.
The lack of understanding and critical appraisal of specialists in general, by non- specialists, is all- pervasive. The field of Forensic Science is no exception. Neither the police, nor the lawyer , nor even the judge appreciates fully the advances or the extensive potentialities of the science.
1. Science for Prosecution- by Grant, J.(London)
2. Criminal Interrogation- by Aubry, A.S.(Springfield)
3. Forensic Science in Criminal Investigation and Trials – by B.R. Sharma
4. Fingerprints: History, Law and Romance -by Wilton,G.,(London )
5. An outline of Scientific Criminology by Morland,N., (Norwich )
6. An introduction to Criminalistics by O’Hara, C.E., and J.W. Osterburg,(Springfield)
7. Principle and Digest of Law of Evidence Act by Monir,M.,(Allahabad)
8. Medical Jurisprudence and Toxicology by Modi N.J(Bombay)
The author can be reached at: firstname.lastname@example.org