J . Forens. Sci. Soc. (1974), 14, 177

The Collection of Forensic Evidence from the Forensic Scientist's

Point of View JULIUS GRANT

107 Fenchurch Street, London, EC3M 5JB, England

The collection and handling of various types of materials encountered by the forensic scientist is discussed with special reference to the author's own experiences with the often conjicting demands of dz$erent aspects of document examination. Case histories, including an account of some scientiJic aspects of the investigation of the attempted assassination of Archbishop Makarios in 1970 are also given.

(This paper was presented at the ScientiJic Symposium of the Society's Annual General Meeting held at the McMorran Hall, City of London Wood Street Police Station on November I 7, 1973.)

When I was asked at rather short notice to speak on this subject my first reaction was to decline because at first thought this appeared to me to be a subject on which only a "Scenes of Crime" officer could speak with competence; and I have no qualifications of this nature. However, onsubsequentconsideration it occurred to me that some rather specialized aspects of the subject, especially so far as they refer to my own work, might be of general interest; and indeed of some use to those whose duty it is to collect evidence.

This paper will, therefore, refer principally to the collection of evidence based on questioned documents, fibres, dust particles and the like. I t will deal not so much with the technique of doing so from the point of view of the scenes of crime officer; but rather with what the forensic scientist would like to do, or expects the scenes of crime officer to do, in order to provide him with suitable material for forensic investigation.

Most forensic scientists would agree that it is desirable for them to attend the scene where possible and to take or supervise the taking of the exhibits they are expected to examine. This is of course often done. However, in my own particular case, since I am retained more often by the Defence, especially in this country, it rarely happens that I visit the scene of crime soon after the event, and opportunities of this kind are therefore usually denied to me. I am therefore, more conscious of the limitations of existing collecting methods when the exhibits reach me eventually.

Perhaps one of the points on which I feel strongest is the method of dealing with documents which have to be both tested for fingerprints by the ninhydrin method, and also examined (usually from the point of view of handwriting comparison) by the document examiner. As is well known the ninhydrin test, even when carried out with the maximum care, is liable to disfigure hand- writing and so to reduce its value considerably to the document examiner. On the other hand, it is normally difficult for the document expert to examine an exhibit and reach his own conclusions without leaving his own fingerprints on it, which will interfere with any subsequent ninhydrin test. If either of these two alternatives is inescapable, the question then arises-who should have the document first, the fingerprint section or the document section? In the British police forces these are two entirely different departments, and in my ex- perience the fingerprint section usually takes priority. I n the case of a person such as myself, who does both fingerprinting and the handwriting comparisons,

the problem is much less acute because the two operations can be carried out virtually at the same time, and certainly on the same premises.

Since the ninhydrin test can disfigure the exhibit, not only from the point of view of deciphering writing, but also to make it less acceptable as an exhibit for production in Court, it is usual to photograph the document in the first instance before any tests are made. However, even when colour is used, this fails to give a truly satisfactory result; and photographs can be of little use for handwriting comparisons where these involve the determination of stroke sequences, since these are not visible in photographs. This applies particularly when the question arises of deciding which of two crossing strokes was made first.

In my view, therefore, when there is the slightest possibility that documents will have to be tested with ninhydrin or otherwise for fingerprints, everybody handling them should wear a pair of protective gloves. On collection the documents should be placed immediately in a transparent plastic envelope, having dimensions only slightly larger than those of the document, and the document should be transported in this form, held between cardboard covers so as to avoid folding or creasing. Documents should, of course, never be folded (other than in existing folds and preferably not at all) by anybody at any stage; and where two or more are discovered joined together, either by pinning, stapling or with paper clips, these should be preserved intact in their positions. The importance of not making a new fold is illustrated by the follow- ing instance. It was alleged that a receipt had been typed above an existing signature on a piece of paper. The paper as received by me had been folded longitudinally, and a very faint ink smear was detectable where the signature touched the sheet on the other side of the fold; this showed that the fold had been made almost immediately after the signature had been written. Examina- tion of the areas where the typescript crossed the fold showed unmistakeably that the typescript was made after the fold, i.e. after the signature. A new fold made by whoever collected the document could have completely obscured the investigation.

Undue exposure to light, e.g. bright sunlight, should be avoided. There is no necessity to seal the envelopes hermetically, but they should be of such a nature that the closure can easily be undone and resealed as required. Each exhibit in its envelope should be labelled on the outside; it is undesirable to put the label inside or to attach it to the document. Naturally, the specimens should not be exposed to any undue extremes of heat, cold, humidity or dryness.

On receipt at the laboratory the documents should first be examined by the handwriting expert. A great deal of his work can be done without removing it from its protective transparent cover. However, when such removal becomes necessary it can readily be done with the gloved hands, and in this connection the thin, disposable plastics gloves now available very cheaply, are useful for the purpose. The document can then be photographed, examined further if necessary, and handed to the fingerprint expert for application of the ninhydrin test. . .- ..

It sometimes happens that tests have to be made on the document other than handwriting comparisons. It may be necessary for instance to examine it in ultraviolet light, to determine the fibre content, or perhaps to analyse the dyestuff used for ruled lines where the question of identity with a comparison piece of paper is involved. It should be taken as axiomatic that all these tests should be done before the application of the ninhydrin reagent, since the chemical contamination of the paper by this reagent could upset the tests involved. In other words, the ninhydrin test in my opinion, is the last test to be made on the document; and not the first, as is so often the case at present.

Fibre comparisons, especially of textiles from clothing, have considerable evidential value, notably in cases of violence and assault. It is very important therefore, that specimens are collected carefully and that nothing of importance

is missed. I t often happens that only a few fibres from say, the clothes of a victim, are to be found on the clothes of the assailant. Sometimes only a few fibres, or even one, is involved. I t has to be remembered that these have been transferred by contact, and they might very easily be lost again unless care is taken in handling the garment concerned. What goes on easily, can drop off easily! I t is now usual, though not exclusively so, to transport such garments to the laboratory in plastic bags, so that any fibres which become removed can be retrieved from the bag. However, in the case of a bulky article, such as an overcoat, it is advisable that two people collaborate in placing the coat in the plastic bag. One should hold the bag open while the other places the article in the bag. In this connection the possibility of contamination of the article from the clothes of the person handling it at the time of the investigation should be borne in mind, and if there is a slightest possibility of this happening, control fibres from the investigator's clothing should also be examined. In the pre- sumably rare cases where it is known that the fibres being sought could be the same as those used in the manufacture of the cloth :s of the investigator, the problem may be overcome by wearing a white overall or other suitable outer covering which will protect the exhibit clothing from contamination by the clothing of the investigator.

I t is appreciated that taking these precautions makes such investigations cumbersome, but there is really no alternative if a sound case is to be built up subsequently. Experience has shown that coloured fibres vary considerably in shade, although they may be the same in chemical composition; or in the make-up of the mixture of dyestuffs present. The only distinguishing feature then would be the proportion of the dyestuffs present. Fibres from men's clothes, especially blue, black or brown suits, often have a common origin, but those from women's clothes are much more varied. Indeed it is an astonishing fact when one considers the tremendous number of women's dresses turned out by one factory, all identical in style, and material, that it is so seldom that one sees two women dressed exactly alike!

The problem outlined above is much less acute when one is dealing with shoes or other footwear, but precautions sometimes have to be taken when the shoes have become contaminated in wet weather and have dried out, and are therefore liable to lose any fibres they may have acquired prior to this process. ,Soils are referred to below in this connection.

The collection of dusts also present problems. The mini vacuum cleaner, as used for cars, is an extremely useful method of scouring fairly big areas, such as upholstery and of course, the interiors of cars. I have used it, with a transformer, from the house mains; or often quite conveniently with a lead from a car battery outside the house. Difficulties sometimes arise in ensuring that all the collected material is removed from the bag of the mini vacuum cleaner, and also indeed that it is quite clean in the first instance. Unfortunately in some types of cleaner, the receptacle must be porous in order that the air drawing the dirt into the cleaner can reach the bag. There are however, cleaners made in which the dust is projected into the bag instead of being filtered out by the air drawn through it, and these offer special advantages, although they are less efficient in operation. The ideal would be a non-textile bag which has the necessary porous properties, but does not contribute its own fibres to the dust collected. In any case it is always a desirable precaution to check the fibres of which the bag is made. This need be done only once and then is good for all time; or at any rate until the bag is renewed. It should be hardly necessary to warn against small holes in the bag, especially at the seams and corners, and it is a good plan to make up the bags oneself with rounded "corners", rather than to rely on those provided by the manufacturers of the cleaners. Even with these precautions it is still advisable to check for holes, and it is surprising how these develop after continual washing of the rather flimsy material. They are obviously not designed for precision work. The cleaner should itself obviously be cleaned between successive operations,

Fig. I . The roof of the Pancyprian Gymnasium. opposite the Archbishop's palace, and the discarded wrapons of the would-be assassins.

(Reproduced frrm the Rlediro-Legal Journal by permission of the editorj

Fig. 2 . The escapr route. (Reproduced from the Medico-Legal Journal by permission of the editor)

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and it should be run "blank" on air and the bag examined, to ensure that it is free from dust, before every operation.

Taping is of course a very useful device in a number of cases, especially where the area to be covered is not very big and is otherwise difficult of access. This applies particularly to seams and pockets. The tape should however, be transported carefully. A method I have found very useful for narrow tapes is to stretch them across the top edge of a rectangular box having a cover, taking care of course, that the adhesive side is face downwards and facing the bottom of the empty box. Where wide tapes are being used a convenient device I have seen employed by the Police, is to place the tapes face downwards on a stiff sheet of transparent plastic. They can then be transported with impunity and even examined in a preliminary way without removing the tape from the plastic surface.

Certain types of sampling exercises present special difficulties, and should be undertaken only by expert samplers. Soils are a case in point; e.g. it is often necessary to compare fragments on a shoe with soil from or near the scene. However, soil in quantity is usually a very heterogeneous material, especially in stony areas or where much vegetation is present (e.g. leaves and twigs, in autumn). Footwear however, can be selective in the ingredients of the soil which it picks up; usually the coarse portions and stones are not to be found. A sample taken without due regard to the differences involved can therefore, lead to misleading results when the comparison is made.

As stated, it is obviously desirable that the forensic scientist should be present a t the scene of the crime as soon as possible after it has been committed. This is not always possible, and in the case of the forensic scientist called by the Defence it is usually out of the question. One particular instance within my experience in which this aspect proved of particular importance, was in connection with the a t tem~ted assassination of Archbishor, Makarios in C v ~ r u s , L in March 1970. I investigated this attempt at the request of the Government of Cyprus. An important exhibit was the jacket of one of the suspects which had a faint smear of powdery material on the right shoulder. I t was inferred naturally, by the Police that this was due to the fact that the shoulder had rubbed against a white-washed wall, and the Police went to great pains to obtain samples from various parts of the building (a school opposite the Arch- bishop's palace) from which the would-be assassins had operated. Figure I

shows their arms after they had been discarded, and Figure 2 shows the area between two parts of the roof through which they made their escape after having fired the shots. This is one of several places where samples were taken of the white-washed walls. I t should be noted in parentheses at this stage that scrapings are of little or no use for this type of work. When a person brushes against a wall he removes some of the surface, and if a scraping is taken from the wall, then some of the material below the surface is removed also, and it is not possible to distinguish between the two. Chemical analysis then becomes quite useless for ascertaining the identity of the white powders.

In effect this is what happened in the present instance, and in fact, the spectrographic analysis of the small dusting of powder on the shoulder of the jacket showed that, among other elements, calcium was present in quantity, and also titanium and cadmium. Calcium was present, but the two other elements were absent not only from the scrapings of the walls taken by the Police, but also from rubbings from the walls which I took myself subsequently. Also the proportion of calcium from the wall rubbings was greater than the proportion of calcium in the powder on the shoulder.

With the collaboration of the Chief of Police, I therefore, attempted to reconstruct what had happened at the time of the attempted assassination. I descended the ladder from the place where the arms are shown in Figure I , and ran along the space between the two roofs shown on Figure 2. I t will be noted that this space is broken up at intervals by 3 gabled skylights, so that anyone running along the narrow corridor must turn sideways in order to pass between

the wall and the skylights. I found that one instinctively turned to the right in so doing, so that the face was towards the wall. However, on emerging from each skylight area I found that the right shoulder was less likely to touch the wall than the square drainpipe which one can see in the photograph just beyond each skylight and running vertically down the wall. Rubbings were therefore taken from the surface of this drainpipe, and these were found to be identical in composition in all respects to the powder on the shoulder of the jacket. It appeared on further examination that the drainpipe, which was made of zinc, had been white-washed over in the first instance, as had the walls. However, evidently this had not taken on the metal surface to the satisfaction of the decorator, and it had subsequently been given a coat of white emulsion paint; and it was this which came off on the shoulder of the jacket, possibly with some whitewash.

In anticipation of the cross-examination I might receive, I spent a good deal of time wandering round the town of Nicosia looking at such drainpipes, and there is at least one to every house! I found that they were either all painted or white-washed or neither painted nor white-washed; and although I spent a half day on this exercise I did not find one drainpipe whose surface covering bore any resemblance to that on the building in question. I t may be added that the sight of me "rubbing shoulders", so as to speak, with drainpipes all over the town gave rise to a certain amount of curiosity on the part of the inhabitants. It should be added further that this, together with other evidence of a forensic nature, was accepted by the Court, and a conviction secured.

Another rather different example of the respect in which the expert called by the Defence is subject to the handicap of retrospective examination in making his investigations and in collecting evidence, is as follows. In the course of a trial involving a shooting affray in London, in which one man was killed and two seriously injured, I was asked to establish whether a particular shot could have been fired from the half-landing of a staircase in the house. The bullet had passed through a panel of the front door and had hit the post of the front gate. During the hearing therefore, I drove down to the place in question and proceeded to fix a piece of string to the bullet mark on the gatepost; and this I passed through a hole in the door and took it back in a straight line to the staircase. The neighbourhood was not a very salubrious one; I was there on my own without assistance and it was not long before I had a large crowd of local inhabitants, especially children, who gathered round and whose remarks and presence did not assist me in my investigations! However, I managed to complete my task despite the handicap of audience and surround- ings. It was quite evident from the position of the free end of the string that the shot could not have been fired from the half-landing of the stairs in question.

I t is hoped that the above miscellaneous examples illustrate the importance of close liaison with the forensic scientist in the collection of forensic evidence; and the handicap to which the forensic expert called by the defence is subjected since he cannot be present at the scene of the crime.