Science and the Criminal

Conflict between the Law-maker and the Law-breaker-Illustrations of Deductive Reasoning in Criminal Cases-Scientific Evidence-Scientific Assistance for the Accused-Instances of Advantages of Conflict of Scientific Evidence-Scientific Partisanship.

In the constant state of warfare between the law-maker and the law-breaker, which began when mankind first organised itself into communities and has existed ever since, every new invention or practical application of scientific discovery has supplied each side with new weapons frequently of much greater precision.

The advantage thus conferred tends to be on the side of the law-maker but not invariably so; for in spite of all the facilities of investigation now available it is surprising how many crimes remain undetected, or how frequently in suspicious cases it is impossible to discover the truth. The law-breaker's primitive weapon of natural cunning has thus often proved more than a match for all the weapons at the disposal, of his opponent.

There is much to be said, therefore, for the suggestion which has recently been put forward on many sides that a department specially trained for the work of criminal investigation should be created.

Under the present conditions the rank and file of the detective force, recruited as it is from the best of the uniformed policemen, contains many men of acute intellect and reasoning capacity, but it cannot be doubted but that in many cases their efficiency would have been enormously increased by a scientific training.

The present system somewhat recalls that under which doctors acquired their knowledge of medicine in the early part of last century. Their mistakes taught them what not to do, but in the meantime the patient sometimes died.

Methods of scientific reasoning so as to draw deductions from observed facts cannot be acquired by solitary night watches upon a "beat," nor does the facility for breaking up a tangle in traffic which the constable acquires as the outcome of his daily duties, necessarily render him more capable of extricating from a mass of confused details the essential facts upon which stress should be laid.

In some of the unsolved mysteries that have occurred during the last few years the presence of a highly trained intellect at the first hour of the investigation might conceivably have led to the detection of the criminal. As a rule, it is only after the first examination is over and the case appears likely to be a difficult one, that the best brains of the department are brought to bear upon the facts, and it may then be too late for effective action.

It should be made possible for a man who possesses a facility for this type of work to join the criminal investigation department without having to go through the routine work of a police constable, which will probably add nothing to his powers of following up a clue; but, on the other hand, this period of probation should be occupied by practical training in scientific methods of working.

The present conditions both of payment and of status are not of the kind that will attract the highest type of brain to the work of criminal investigation, and yet there is no reason why it should not be made to offer the advantages of other branches of professional work.

An apt illustration of the use of acute observation and deduction in solving a mystery is afforded by the strange story of a shooting accident, that, according to a writer in one of the leading morning papers, took place many years ago.

A country gentleman was found lying dead upon a sofa, with the whole of the charge of a sporting gun in his body. The discharged gun was hanging in its usual place upon the wall, and there were no indications of any struggle having taken place. All the circumstances apparently pointed to the man having been murdered in his sleep, for it was impossible for him to have shot himself and have then replaced the gun upon the wall, and strong suspicion fell upon one of the servants in the house.

This man was arrested, and would probably have been convicted had it not been for the detective noticing that the dead man's watch, which had been smashed by some of the shot, had been stopped early in the afternoon, and that at exactly the same moment the sun was focussed through a bottle of water that was standing upon the table in such a way that the ray fell upon the nipple of the gun upon the wall.

Accordingly he loaded the gun again, hung it in the same spot, and placed a dummy figure upon the sofa, and as soon as the sun's rays passed through this unintended burning-glass and were focussed upon the gun, an explosion occurred and the contents were discharged into the figure.

The writer has been unable to trace the date of this occurrence, but even if it is not founded upon fact it is not impossible, for there are undoubtedly cases where papers have been set on fire by the rays of the sun being concentrated upon them, through a bottle of water.

An instance of the way in which one small fact may give conclusive proof that a crime has been committed is afforded by the trial of Swan and Jefferies in the early part of last century.

The prisoners, who were indoor servants, had committed a murder and then raised an alarm with the object of throwing the suspicion upon burglars, who they alleged had broken into the house. But an examination of the grass outside the house showed that although dew had fallen heavily through the night there were no indications of its having been disturbed by footsteps. This piece of circumstantial evidence led to their arrest, and they were subsequently convicted and executed.

Equally convincing were the clues that led to the arrest of Courvoisier in 1840, for the murder of Lord William Russell, who was then seventy-five years of age.

The prisoner had only been in the service of the murdered man for a short time. He stated that on the night before the murder he had left his master reading in bed, as was his frequent custom, and a fact in support of this was that the candle had burned down to the socket.

Early in the morning the housemaid found the silver plate scattered about the room, and various articles of value tied up in bundles, as though burglars had broken into the house and had been interrupted in their work.

She called Courvoisier, and he appeared almost immediately, fully dressed, and going into the room of Lord William Russell found him with his throat cut.

On a door were marks which indicated that it had been broken in by the supposed burglars, but closer examination showed that the damage had been done from the inside. In addition to this, any burglars entering the house through this door must have passed over a wall, and this was found to be thickly coated with dust which had not been disturbed.

For a long time no trace of the missing valuables were discovered, but finally after a thorough search of the premises, some of the money was found hidden behind the skirting in the pantry of the accused, while later on the stolen plate was discovered in the keeping of a man with whom Courvoisier had formerly lived.

Mainly on the circumstantial evidence of these facts the prisoner was convicted; afterwards he made a full confession of the crime.

Clever deductive reasoning was also shown in the following case, in which the author of a shooting outrage that occurred in 1831 at Ayr was discovered in a singular manner. Someone had maliciously fired a gun into a church, and had hoped to escape detection. It was noticed, however, that some of the bullets, after having passed through the windows, had left a mark upon the wall opposite. By drawing a straight line between these marks and the holes in the windows, and extending the line outside the church, the other end was found in a window on the other side of the street. Subsequently other proof was obtained that the gun had been fired from this window.

Numerous cases might also be quoted where the trained observation of a doctor has called attention to some slight point which would otherwise have been overlooked, but which has furnished the clue to the detection of a crime.

In the year 1806 a man named Blight was shot with a pistol at Deptford by someone unknown, and died from the wound. Sir Astley Cooper, who was called in to attend to the victim, carefully noted the relationship of the body to other objects in the room, and from the position of the wound concluded that the shot had been fired by a left-handed person. This inference drew suspicion upon a gentleman named Patch who was the only left-handed person who had been seen with Mr. Blight. He was a close personal friend of the latter, and no one had dreamed of suspecting him of the crime. The results of further inquiries proved that this man had fired the shot, and after his conviction he confessed that he had been guilty of the murder.

The fact that a weapon is tightly held in the hand of a person who has been shot is strong presumptive evidence that it is a case of suicide, since it is improbable that the hand of a dead man could subsequently be made to grasp a pistol.

There is a remarkable case on record, however, in which the fact that a pistol was found clenched in the hand of a dead man was at first regarded as evidence of a murder. A son of the deceased, who had slept in the same room was accused of having killed him and of then placing the discharged pistol in his hand to give the suggestion of suicide. Experiments were made in which the hand holding the pistol was lifted into the position in which it must have been held if it had been a case of suicide, and in each instance the hand, when allowed to fall, did not retain the pistol. For the defence medical evidence was given that the spasmodic contraction of the muscles after death would account for the pistol being still clenched in the hand, while the inability of the hand to grasp it afterwards did not prove anything. Evidence as to the presence of a motive was given, but the scientific evidence was regarded as decisive and the prisoner was discharged.

The question whether a person who has apparently committed suicide could possibly have made use of the degree of force to which circumstances pointed has frequently arisen.

The most notable instance of the kind was in reference to the Earl of Essex who was found dead in the Tower in July, 1683, his throat having been cut. A razor was lying by his side with its blade notched, and public opinion was strongly divided as to whether he had committed suicide or had been murdered. The medical men who supported the former view explained the notches upon the razor blade as the result of its having been drawn backwards and forwards across the neck bone, although for a suicide to have done this would have been an impossibility.

Occasions have arisen where a chemical expert has been asked to state whether a gun or pistol found lying near a body has or has not been recently discharged.

Even in the case of firearms that had been loaded with black powder no very definite answer can usually be given to this question. Taylor suggested that the presence of potassium sulphide (formed from the powder) adhering to the barrel would indicate that the gun had recently been fired, whereas after a short time this sulphide would become oxidised, and no longer give the reactions of a sulphide. After a longer time traces of iron oxide formed from the iron of the barrel might be expected.

It would not be safe to lay stress upon conclusions based upon such data as these, and at best they could only afford corroborative evidence.

An amusing instance within the present writer's experience affords another example of the way in which a trifling point being overlooked may be strong presumptive evidence of attempted fraud. A family of the name of, say, Abendessig, effected an insurance against burglary with a company which may be described as the Safeguard Assurance Co.

It was not long before they were the unhappy victims of a burglary in which Miss Abendessig lost several valuable pieces of jewellery including a watch, a diamond ring, and several brooches.

In proof of her claim she produced receipts from the jeweller from whom she stated she had bought these articles, the total value of which was given at ￡150.

There were three receipts in all, dated at intervals of two or three months, the first being made out to Miss Abendessig and the last to Mrs. Lab, she having been married in the interval, and the second to her father, Simeon Abendessig.

The Safeguard Assurance Co. had a suspicion that the jeweller, who had an address but no shop, was in league with the Abendessigs, and that the first and third receipts had been written at the same time.

The present writer was therefore asked to examine these documents to see whether any evidence of the date of writing could be obtained.

They were both written in blue ink upon common billheads, but the fact that the ink and paper were of the same kind was no proof that they were not genuine receipts.

When, however, the receipt stamps were examined under the microscope it was obvious that the right-hand side of one stamp corresponded with the left-hand side of the other stamp. That is to say, the little projections of paper left when two stamps are torn apart across the perforation exactly coincided in every instance, a long projection on one being matched by a short projection on the other, and so on.

The exact coincidence of seventeen points could not have been the result of chance, and the stamps on the two receipts must therefore originally have been attached to one another in the sheet.

The further inference was that the jeweller must either have torn them apart and put one on the earlier receipt and the other on the later one at the same time, or he must have had the second stamp put aside for three months and then affixed it to the later receipt.

A much more obvious slip than this was made some years ago in a bogus claim upon a fire insurance company, the story of which is related in Lord Brampton's "Reminiscences." The fire broke out on the premises of a firm of tailors, and it was claimed by them that the whole of their stock, including many hundred pairs of trousers, had been destroyed.

The insurance company, after examining the burnt-out building, instructed a number of their agents to sift carefully the whole of the ashes.

At the hearing of the case the counsel for the company remarked that it was strange that in a fire in which so many pairs of trousers had been burned the metal buttons upon them should not have been found.

On the next day the tailors appeared with a whole bucketful of buttons, but their production was too late to be convincing, for the ashes had been thoroughly sifted before the claimants attempted to make good their oversight, and only a very few trouser buttons had been discovered.

On the other hand, the danger of jumping to a sudden conclusion from circumstances has been frequently demonstrated. Thus, a very extraordinary case in which some facts that clearly pointed to the guilt of a prisoner were found to have misled many witnesses, was tried in 1813 at the assizes at Bury St. Edmunds. A farmer who owned upwards of 1,200 acres was accused of burglary, and as evidence against him it was positively stated that certain articles in his possession had been stolen from the house. The witnesses swore that they had identified some sheets by stains upon them and a cask by the fact of its being marked with the letters P.C. 84 in a circle. For the defence, witnesses stated that the prisoner was in possession of sheets stained in exactly the same way, and that the cask was one of those in which he had received cranberries from Norwich, all of which casks were marked in the same manner. The prisoner was acquitted.

Scientific testimony is another form of the so-called "circumstantial evidence," and as such is sometimes looked upon with suspicion. Yet in how few cases is it possible to produce the man who can say, "I saw the deed done," and even in such cases, what errors of identification may occur! In far the greater number of crimes the proof must depend to a large extent upon the evidence of circumstances. But these must be so convincing that it is impossible in reason to draw any other conclusion from them. In this country it is the duty of the prosecution to prove the guilt, and unless that is done in such a way as to leave no shadow of doubt in the minds of the jury, a prisoner is entitled to be acquitted.

There must be no speculation upon a man's guilt. A man is regarded as innocent so long as it is impossible to connect to him the last link in a long chain of circumstantial evidence.

In the brief accounts of various celebrated trials in the following pages an attempt has been made to give an outline of the scientific circumstantial evidence that has led to the conviction or acquittal of the prisoners. In some of these trials proof of guilt has been overwhelming, although the testimony of an eye-witness has been lacking, but in others the Scotch verdict of "Not proven" (a curious equivalent of which, however, was once given in the trial of Mrs. Rudd) would be a more fitting deduction from the evidence, than the alternative of "Guilty" or "Not guilty," which is all that is allowed by the English law.

A good illustration of the value of scientific proof was seen, in 1884, at the trial of a woman named Gibbons on the charge of having shot her husband.

For the defence it was urged that the man had committed suicide. There were four bullet wounds from a revolver in the body, and the medical evidence went to prove that although any one of the wounds might have been inflicted by the man himself, it was extremely improbable that all of them had been. Moreover, some of them were in such a position that they could only have been self-inflicted if the revolver had been held in the left hand, whereas witnesses testified that the deceased was not left-handed. The prisoner was found guilty.

Attempts have frequently been made by defending counsel to obtain permission for a scientific man to be present on behalf of a prisoner at any examination made before a trial, but all such requests are invariably refused.

It is quite a common occurrence, however, for the evidence given by scientific witnesses for the prosecution to be controverted by scientific witnesses for the defence, and the most recent instance of the kind at the trial of Crippen will be fresh in the memory of everyone. Where there is any possibility of doubt it should be possible for every prisoner to obtain scientific assistance.

An accused person who lacks the means to procure legal assistance in his defence has assigned to him by the Court a barrister who will represent his interests and see that they do not suffer from ignorance of legal technicalities.

This principle might well be extended so as to cover the ground of scientific evidence. Under the present conditions the prosecution has unlimited facilities for applying every description of test, but it has not always been easy for the representatives of the accused person to obtain scientific help in criticising the nature of this evidence.

Scientific evidence should be, and usually is, quite impartial, but the everyday conflict of honest opinion in civil actions illustrates the possibility of mistakes occurring or of certain points that would tell in favour of the accused being overlooked.

For instance, suppose a stain on the clothes of a person accused of murder were examined by a chemist for the prosecution and found to consist of blood. The fact would tell against the accused, even though the witness (as in a recent case) could express no opinion whether it was human blood, or the blood of an animal. Assuming in this hypothetical trial that the blood stain was really due to rabbit's blood, another chemist representing the prisoner might be acquainted with the comparatively recent physiological methods of distinguishing between the blood of different animals, and thus be able to prove the real nature of the blood stain and break one of the links in the chain of evidence.

In most of the important criminal trials the scientific evidence is given by more than one witness, and the possibility of mistake is thus greatly reduced, but this is not invariably the rule.

Scientific criticism derived from a first-hand examination of the material would be of much more value than the criticism of the statement of the results, and might have considerable weight upon the conclusions of the jury.

A defending counsel cross-examining a scientific witness is usually dealing with an unfamiliar subject, and lacks the specialised knowledge that would enable him to point out the weak points in the evidence.

When a wealthy person is on trial, however, the counsel has the advantage of getting the best expert advice upon the scientific matters put forward in evidence, and is thus able to lay stress on all that will help his client, but a poor prisoner lacks this advantage, and therefore runs a greater chance of being convicted.

An early trial in which the prisoner owed his acquittal to a conflict of scientific evidence was that of Spencer Cowper, the grandfather of Cowper, the poet, who was tried at the Hertford Assizes in 1699 for the murder of a young gentlewoman named Sarah Stout.

With Cowper were also tried several of his friends, whose remarks having been overheard had suggested that they were aware of what had happened to the girl.

Cowper, who was a barrister, defended himself and incidentally his companions. The story told by the prosecution was that at the previous Assizes the prisoner had stayed for a night at the house of Mrs. Stout, the mother of Sarah Stout. The servant-maid stated that she had been told to prepare Mr. Cowper's bed, and that when she came downstairs again, it then being about eleven o'clock in the evening, he had gone out, presumably with Sarah Stout, who was never again seen alive. The next day her dead body was found floating upon the river.

The condition of the body was, it was asserted, conclusive proof that she had been strangled and then thrown into the water; for, to quote the words of the counsel for the prosecution, "when her body came to be viewed it was very much wondered at; for in the first place it is contrary to nature that any persons that drown themselves should float upon the water. We have sufficient evidence that it is a thing that never was; if persons come alive into the water, then they sink; if dead, then they swim. At first it was thought that such an accident might happen though they could not imagine any cause for this woman to do so, who had so great prosperity, had so good an estate, and had no occasion to do an action upon herself so wicked and so barbarous. Upon view of the body, it did appear there had been violence used to the woman; there was a crease round her neck, she was bruised about her ear; so that it did seem as if she had been strangled either by hands or a rope."

The evidence brought forward to support the theory that Sarah Stout had been killed, before being thrown into the water, included that of several local doctors who had examined the body, and also that of several London doctors who were called in as expert witnesses.

These all gave as their opinion that the body of a person who had been drowned must contain water in the thorax, and that since no water was present in the body, death must have been caused in some other way. Two seamen of the Royal Navy were also put into the box, and both were emphatic in their opinion that the body of a person who had been drowned would sink, while a dead body thrown into the water would float.

Spencer Cowper, who, as has been stated, conducted his own defence, cross-examined the medical witnesses and made them admit that they had no knowledge of the way in which the body of a person who had drowned himself would behave.

He entered a strong protest against the body having been examined after the coroner's inquest (at which a verdict of suicide while of unsound mind had been found) by medical men acting in the interests of the relations of the dead woman, with the intention of becoming prosecutors. "If," said he, "they intended to have prosecuted me or any other gentleman upon this evidence, they ought to have given us notice, that we might have had some surgeons among them to superintend their proceeding. My Lord, with submission, this ought not to be given in evidence." The judge overruled this objection, saying that supposing an ill thing had been done in taking up the body without some order, that was no reason why the evidence should not be heard.

In further cross-examination Mr. Cowper succeeded in throwing doubt upon the statements of witnesses, who alleged that they had seen marks of strangling, and produced witnesses to prove that any marks upon the body had been the result of contact with stakes in the bed of the river. Then he brought forward his own expert medical evidence, which was given by ten of the leading doctors of the day, including Sir Hans Sloane and the celebrated surgeon William Cowper. These held a different view from that of the doctors called for the prosecution, and gave their reasons for concluding that the appearance of the body was quite consistent with death by drowning.

Some described experiments they had made upon animals, which proved that when killed and thrown into the water the body sank at first and then rose to the surface, and also that drowning could take place without much water being swallowed.

As proof of the dead woman having been of a melancholy disposition and not of sound mind, letters of hers were read to the jury, but these her mother and brother would not admit were in her handwriting, since, they asserted, it did not suit her character. (See p. 85.)

The judge, Sir Henry Hatsell, in summing up confessed that he was very much puzzled, and that he perceived that "doctors do differ in their notions about these things."

The conclusion of his remarks is worthy of quotation: "I am sensible I have omitted many things; but I am a little faint, and cannot remember any more of the evidence."

It is not surprising that, soon after Queen Anne came to the throne, he was removed from the bench.

The jury believed the medical witnesses for the defence, and after a short discussion found Spencer Cowper and the other prisoners "Not guilty."

To come to more modern times, the advantage of a conflict of scientific opinion to the accused was seen in the celebrated Maybrick poisoning case. At the trial evidence was given by Professor Tidy to the effect that the symptoms and appearances were not those of arsenical poisoning and that the amounts of arsenic found in the body were not greater than those present in cases where arsenical medicines had been taken months before death, and where there was no suspicion of poisoning. Although the prisoner was convicted and sentenced to death, there can be little doubt but that this evidence had an important influence in determining the subsequent alteration of the sentence to penal servitude.

There is no necessity for such scientific assistance given to the defence to degenerate into partisanship, such as was shown at the trial of Palmer for poisoning in 1856. That case was characterised by many remarkable features, the suspected person, for instance, being allowed access to the bottle in which had been placed the material taken from the body for analysis, and also being given the opportunity of attempting to destroy it.

Prior to the trial, Taylor, the chemist who was to give evidence as to the presence of poison in the body, communicated with the papers, while Herapath, one of the witnesses called for the defence, publicly accused Taylor of incompetence.

So acrid were the statements of the scientific witnesses for the defence at the trial that the judge commented in vigorous terms upon their evidence as having been given with the object of obtaining an acquittal at all costs. "It is indispensable," he said, "to the administration of justice that a witness should not be turned into an advocate, nor an advocate into a witness."

In another poisoning trial which took place three years later, the chemical evidence brought forward by the defence resulted in the prisoner being set free, after having been sentenced to death. In this case a doctor named Smethurst was accused of poisoning a young woman named Isabella Banks.

Dr. Taylor, who was the chief chemical witness called for the prosecution, had found arsenic in material from the body, although he could not detect any remaining in the tissues. On the other hand, Dr. B. W. Richardson, who was called as a witness for the defence, stated that arsenic was a cumulative poison, and that if it had been given for a long period, as alleged, traces must inevitably have been present. Hence in his opinion the absence of arsenic in the tissues was conclusive proof that death was not the result of slow arsenical poisoning.

The medical evidence called by the defence, also left room for some doubt as to whether death might not have been the result of dysentery, the symptoms and appearance, it was alleged, being as consistent with that cause as with arsenical poisoning.

The scientific witnesses for the defence did not succeed in convincing the jury, but after sentence of death had been passed the judge forwarded the papers to the Home Secretary, and advised that the opinion of an independent scientific authority should be taken. Accordingly the whole of the chemical and medical evidence was studied by Sir B. Brodie, whose report was that there were six reasons which led to the conclusion that Smethurst was guilty, and eight reasons which pointed in the opposite direction; and that, therefore, the impression left upon his mind, was that the proof of Smethurst's guilt was not absolutely convincing.

The Home Secretary, on receiving this statement of opinion from his scientific referee, immediately granted a free pardon. In this case, but for the conflict of scientific opinion upon the medical and chemical evidence the prisoner would have been hanged.

Instances such as these might be largely multiplied, but the above are sufficient to show that a scientific defence may succeed in breaking down the scientific evidence brought by the prosecution in criminal cases; or, failing that, may (as in the Maybrick case) help to bring about a commutation of the sentence.

There is thus abundant justification for the plea that the poor prisoner should have the same advantages as regards scientific assistance as he now possesses in legal matters, and thus be placed on an equality with a wealthy prisoner.

It ought not to be a difficult matter to draw up a list of men of recognised standing in chemistry and medicine, who would be willing to serve in this capacity when selected by the judge in a trial.

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