021. WHAT DO THE ABRASIONS TELL US?

I had a tremendous for my article " The use of infra-red photography in Forensic Science", published in the October,1994 issue of Crime & Detective. Many readers however could not understand properly, what I meant by infra-red rays. Mr. Suryaprabh writes from Pune," Your article on detecting blood stains was superb. But I could not understand much about infra-red rays. Could you tell me more about them in your feedback column?" Well Suryaprabh, I had decided not to put too much science in my article, but since you have asked me this question, let me tell you about infra-red rays in as simple words as I can. Ordinary light is composed of rays, which move in jumping fashion. If you had the means to see these rays, you would find that these rays move forward by jumping, much as frogs move forward by jumping. The distance through which these rays jump is different for different rays. For instance, rays of blue coloured light make very short jumps, while rays of red coloured light make very long jumps. Rays of all other colours make jumps of intermediate distance. There are some invisible rays which make shorter jumps than that made by blue coloured light. These are known as ultra-violet rays. You must have read them in connection with solar eclipse. Then there are certain other invisible rays, which make longer jumps than even the red light. These are known by the scientists as infra-red rays. Both ultra-violet and infra-red rays are very helpful to forensic scientists. Although they are themselves invisible, they make several other things visible. In the October issue we have seen, how these rays made the various blood stains visible, which were invisible otherwise. Just for the sake of additional information, I would like to add up something more. You must have heard about microwave ovens. Many of you might even be having one at home. These microwave ovens use another kind of invisible ray, knows as microwaves. These rays make jumps even longer than the infra-red rays. Similarly X-rays (which are used for diagnostic purposes in hospitals), are yet another kind of rays which make shorter jumps than even the ultra-violet rays. There are a number of other rays familiar to scientists and they make full use of them in several ways.

This time I am going to you about a remarkable case which I solved about 3 years back. In 1992, I was asked to do the post-mortem examination on the dead body of a 45 year old man Pyare, who had died in a drunken brawl. He had gone to his friend Mohan's house for a drink. They started playing some kind of card game there. It involved money also, so in fact they were gambling. During the course of play, an altercation developed between the two, and Mohan, in a fit of rage threw a glass ash-tray towards Pyare. It hit Pyare on the forehead and he dropped dead immediately. Mohan had a set of two similar looking ash-trays. Many friends who used to visit his house testified that he indeed had two similar looking ash-trays. When the police searched Mohan's house after the incident, they found only one ash-tray in his house. When questioned regarding this, Mohan said that one ash-tray had broken accidentally some days back and he had thrown away the remains of that tray. Actually something else had happened. After the ash-tray hit Pyare's forehead, it fell on the floor and broke down and Mohan threw away the remains. His story was that Pyare had consumed a lot of alcohol and when he was returning home, he had fallen down the stairs and had died as a result. The police picked up the remaining ash-tray and gave it to me in the hope that it might help my work. I found that if somehow I could prove that Pyare had indeed been hit by the ash-tray, the police could nab Mohan. I did it in quite an ingenious way. Actually I found an abrasion on Pyare's forehead which gave Mohan away. But to understand properly the details of how I nabbed Mohan, we must know a little bit about abrasions.

Abrasions are very superficial injuries, which are produced when the skin rubs against some rough surface. If we could look at the skin under a microscope, we would find that it is constructed rather like an onion, having several layers. Just as you can peel several layers of thin coverings from an onion, the same can be done with the skin. The skin is composed of two layers, the upper being called epidermis and the lower dermis ( The upper layer is further composed of five sublayers, giving the skin a true resemblance to an onion as talked earlier, but this aspect is not necessary for the purposes of this story, so I will not elaborate it further). Epidermis does not have any blood vessels, so if something injures only the epidermis, there will be almost no bleeding. Abrasions are injuries which cause damage only to the epidermis and that's why there is usually very little bleeding from abrasions. Abrasions can be quite useful in knowing the events before death. If a person was dragged on a rough ground there will be abrasions on his back. These abrasions will tell a forensic pathologist that the person was dragged on rough ground. Not only this, these abrasions can also tell the direction in which the body was dragged. The abrasions are quite deep in the direction in which the body was being dragged. In the other direction ( i.e. the direction away from that of dragging), these abrasions can be quite superficial. This gives us the direction of dragging which can confirm or refute the statement of so-called eye witnesses. Thus if the victim was dragged by catching hold of his feet, the drag marks (abrasions) will be deeper near the feet end, and if he was dragged by catching hold of his arms, the abrasions will be deeper near the head end. In this particular case, the killer raped a young woman, and then killed her with a knife. While he was raping her, another young woman heard her cries and rushed to the spot. The scene that she saw through the bushes was too horrifying. She was too scared to come out of the bushes and help her friend. But she kept watching the killer and his actions. After satisfying his lust, the killer stabbed the woman, to remove the possibility of her going to police later. Then he dragged her by her feet, and ditched her in a nearby nallah (nallah is an Indian term which means a small stream of water - generally it refers to open sewage water stream). The killer was caught in due course of time, and the young woman, who had watched her through the bushes, gave the details of what she had seen. Her statement was challenged by the defence counsel on several grounds. It was said that she had been tutored by the police to depose against the killer. She was grilled by the defence counsel on several grounds. One of the grounds was that she had not seen the dragging of the body by the killer and was saying this merely to make the story more ghastly and also because of being tutored by the police. According to the defence story, the unfortunate woman might have fallen in the nallah just by accident. The post mortem examination showed that there were abrasions on the back, which supported the story of her being dragged by someone. Not only this, the abrasions were deeper near the feet end, and this supported the woman's story that the victim had indeed been dragged by the feet.

If the abrasions are situated in more than two directions, the probability is that the deceased was dragged repeatedly in more than two directions. In this figure we see abrasions in more than two directions. This was the case of a woman who was first murdered and then thrown down a deep pit. During the fall, the body of the woman struck the wall of the pit twice, in different postures. This gave rise to two sets of abrasions, both in different directions. If this body had been given to me even without any accompanying story, I would still have been able to say, just by looking at the abrasions, that something weird had happened to the lady. It could not have been a case of simple dragging, simply because the abrasions were running in completely different directions. A case of simple dragging would have caused abrasions in one direction only.

However most interesting are the abrasions which are caused by peculiar shaped objects. These are interesting because they reproduce the shape of the object causing them, and this helps us identify the object. These abrasions are known as patterned abrasions because they are exactly similar to the pattern of the object causing them. It is important to understand how they are caused. A rough object upon hitting the skin crushes the upper layers of the skin, causing abrasions. If the object has some pattern (such as the radiator or the tyre of a car), the abrasions will assume the same pattern. This happens because the pattern on the rough object crushes only those layers of the skin which come in contact with the pattern. It is rather like making the mark of a rubber stamp. A rubber stamp has certain raised areas and only those areas come in contact with the ink and subsequently with the paper. Thus we get a peculiar mark (such as the name of a company or a person). If the same stamp were made of a hard substance such as a stone, and it were strongly imprinted on the skin, a patterned abrasion will form exactly in the same shape. The patterned abrasions are thus very helpful in identifying the weapon causing them. Let us see this by a few illustrations.

In one of the cases, the deceased was attacked by a `Rambo knife'. The back edge of the serrated knife produced tell-tale patterned abrasions. These abrasions clearly give the shape of the weapon. During the investigation of the case, three suspects were caught, and several knives were recovered from all of them. But only one suspect had the peculiar knife, which could have caused such peculiar looking abrasions. It could be easily proved by the forensic pathologist that only that knife could have produced the peculiar abrasions seen on the body. The suspect was prosecuted on this vital piece of evidence. Thus the patterned abrasions helped nab the killer. In another case a man fell against a ridged tiled surface. The pattern produced on his head helped to reconstruct the events before death. Normally one would have thought that he was killed, but the peculiar looking abrasions supported the story that he might have fallen against the ridged tile.

Coming back to our case. I saw a pattern similar to the one shown in the figure here. The head is showing a very definite and clear patterned abrasion. It consists of concentric circles. When I examined the ash-tray which was given to me, I found a similar pattern on the base. The story at once flashed in my mind. Mohan had hit Pyare with the ash-tray which had caused the peculiar looking abrasion. Like the mark of a rubber stamp, the ash-tray had left its impressions (patterned abrasions) on the forehead. Had Pyare fallen down the stairs as alleged by Mohan, he couldn't have sustained that peculiar looking abrasion. The reasoning is simple. If you see the mark of a rubber stamp anywhere on a paper, you are sure that there must be a similar stamp somewhere, and it must have been used on the paper. Similarly when I saw the patterned abrasion on the forehead (which in many ways is just like the mark of a rubber stamp, as explained earlier), I was sure that some object with a similar pattern must have been used to hit Pyare. Without that object, the mark simply could not have appeared on the forehead! Under the weight of the forensic evidence, Mohan cracked and admitted his guilt. Thus a very small and insignificant looking abrasion revealed the whole crime to me.

Note: Certain figures mentioned in the text may not be visible here. Although not being able to look at the figures would not interfere with the comprehension of the article very much, if it is desired to have a look at the figures, readers are advised to consult the original text in the magazine.

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