Forensics: exact science or dramatized fiction? #10
As stated in my earlier article on the ballistics evidence, the so-called forensic experts claim many things which are scientifically impossible. In the current article, our attempt will be to expose the ‘hole’ truth.
Entry wounds cannot tell anything significant
A great deal of outdated misinformation prevails among police officers and self-styled forensic experts. Many policemen and forensic experts claim that they can tell the calibre of the bullets just by looking at the entrance wound. This is simply not possible. The fact is that no study of the appearance of entry wounds can positively link them with a particular bullet—that is a scientific impossibility.
There are a large number of complicating factors. Even when two bullets of different calibres strike at 90 degrees, the elasticity of the skin tends to obscure the size of the opening to such an extent that there is no way of finding out the diameter of the hole that must have been made at the moment of contact. After the bullet passes through, the elasticity of the skin causes it to return to its former size and the edges of the wound contract.
More importantly, there is no reason to believe that the bullets will always be striking at 90 degrees—on the contrary, except for cases of point-blank shooting, practically all bullets will strike at an angle. A smaller calibre bullet, which strikes at an acute or obtuse angle, will obviously produce a hole much bigger than its calibre and thus confuse the Indian forensics.
A tumbling bullet will produce an absolutely unpredictable effect. The bullet could tumble after hitting a hard object, for example, before it reaches the body—such as a pen kept in the breast pocket, or maybe some coins in a wallet. Brian J. Heard concludes in his ‘Handbook of Firearms and Ballistics: Examining and Interpreting Forensic Evidence’ that in skin and fabrics, nothing significant can be made out from an examination of the entry wounds.
X-rays are misleading
Indian forensics have a very bad habit of commenting on the calibre of the bullets from an X-ray. The simple scientific fact is that X-rays can only tell you about the location of the bullet, not its calibre. Remember that X-rays are two-dimensional image projections or shadows of a three-dimensional object on a two-dimensional film and, as anybody familiar with the science of maps or shadows knows, creates misleading distortions. If one is really keen to address this issue then we must take two X-ray photographs of the body, one face on and one side on. These can then be used to estimate the depth of the projectile in the body. A number of bullets of different calibres can then be placed alongside the body at a suitable position and then X-rayed to estimate the bullet calibre. Where in India do they have these facilities and resources or even the technical knowledge to apply them?
Shotgun pellet wounds could be confusing
From a visual inspection, only shotgun pellet wounds are distinct from bullet wounds. However, even in respect of those, Indian forensics and police officers do not know that if large size bullets such as LG (British—0.36 inch or 9.14mm diameter of each pellet) or #1 Buck (American—0.30 inch or 7.62mm diameter of each pellet) are used, their sizes are practically the same as those of 9mm pistol or 7.62mm rifle bullets! The ignoramuses in the Indian police and medical fraternity presume that if a shotgun has been used the pellets would necessarily be No. 9 pellets (both British and American) of 0.08 inch or 2.03mm diameter, which people commonly use for shooting small birds. Obviously, there is no reason to subscribe to such a notion when different size shots and even slugs are available in India.
Exit wounds are not always bigger by the book
Similar myths prevail regarding the exit wounds also. Most ignoramuses in the police and forensic experts think that the exit wounds must necessarily be a big hole with a ragged appearance. It is not necessary. There may be situations when the exit of a bullet is at a point that is well supported, either by tight clothing such as a belt, waistband or corset or where the victim was pressed against a firm surface such as a wooden or plasterboard wall, upholstery, etc. In those cases, the pressure of the external substance tends to hold the skin surface rigid, causing the exit would be a clean puncture, sometimes indistinguishable from the entrance wounds except for the absence of inversion, abrasion ring and another soiling. In fact, it may become extremely difficult to distinguish entrance from exit wounds if the body is decomposed, especially after maceration due to immersion in water.
The hoax of ricocheted bullets
In India, whenever the police have to deny that they had shot someone intentionally, they cook up the theory of ricochet and everyone believes it. It is a much rarer phenomenon than what they would like the public to believe. When a bullet strikes any surface, there is a critical angle at which the bullet will bounce off or ricochet from the surface rather than penetrate. As Brian J. Heard notes, it is extremely difficult to predict this critical angle for any bullet/surface configuration. Factors such as bullet shape, construction, velocity and the nature of the ricocheting surface all have a pronounced effect on the outcome. It must also be kept in mind that after ricocheting from the surface, the missile will lose a considerable amount of its velocity (up to 35% in test firings) and, invariably, lose its stability.
Hard jacketed, high-velocity bullets striking hard surfaces are more likely to ricochet. This means that if the police are cooking up a story of an unjacketed revolver bullet (a large number of cops in India still use revolvers) ricocheting off a cement-plastered brick wall, they are obviously telling a lie. Their lies can also be busted by an examination of the possible angle of ricochet. In most cases of bullets ricocheting from a hard surface, the angle of ricochet is generally considerably less than the angle of incidence.
When police claims ricochet, it must be kept in mind that bullets invariably lose their gyroscopic stability and tumble after ricocheting. Hence, if an injury is caused by a ricocheted bullet, it shall not have a clean entry hole. It is likely to be a quite big hole. Further, it will then go on to produce an even more irregular wound channel. Jacketed bullets often tend to break up on ricocheting, peppering the skin with a jacket and lead core fragments. Finally, bullets that have ricocheted from glass, steel, concrete or wood have a very distinctive flat spot which is characteristic of the material where the contact has been made. This contact point will often have paint, wood fibres or concrete adhering to it for easy identification. If such examination is done or demanded by the defence, most of the false stories of ricocheted bullets can be disproved in court.
The myth of powder marks, smoke blackening or power tattooing
Smokeless powder based on nitrocellulose and guncotton etc. was introduced in 1884. Before that, black powder (gunpowder) was used as a propellant in cartridges. Black powder burns relatively slowly. This means that the gases produced by the combustion of whatever part has combusted fully will also throw out the un-burnt particles of charcoal and sulphur etc. along with it. In any case, because of charcoal in it, there would be particles of ash also even in the smoke of the combusted particles. If the handgun is fired close to the body, these particles would stick to the skin producing what is known as powder marks, smoke blackening, powder tattooing, smudging, fouling, stippling or peppering. They may range from a millimetre size down to minute specks, either black, blue or orange in colour, though pigmentation of the skin may obscure the finer appearances. The effect is relatively less in a long-barrelled gun.
If the gun is fired close to the body, the hot gases and flame can also singe the body hair and the skin. The flame from the muzzle reaches a few inches in the case of a revolver and up to a foot from a shotgun. However, today’s ignorant police officers and forensics do not know that even in the era of black powder cartridges, old-timer crooked cops had invented a technique of masking powder marks. They used it for fake encounters. All they needed was a wet towel placed on the body of the victim. The wet towel blocked the flame as well as trapped the un-burnt powder particles—that is, there would be no singeing, no tattooing even if the victim was shot from point-blank range.
Also Read
Forensics: exact science or dramatised fiction? #1
Post mortem reports – the big farce, justifying untruth
Ballistics- evidence at Gunpoint
The forensic community does not know that smokeless powder, which is in use for the past 137 years produces very little residue in comparison to black powder and powder marks are not prominent. These might deposit a greyish discolouration rather than black. The intellectual bankruptcy of the Indian police officers and ill-informed forensic experts is such that they still look for powder tattooing even as it is almost impossible to get a black powder cartridge these days. Public prosecutors still wax eloquent about powder marks in Courts and nobody tells them to shut up!
Finally, the court debunks the popular myths
In Anand Kumar And Ors vs the State of Haryana (on 15 February 2019) the Punjab and Haryana High Court cited extensively from Alfred Swaine Taylor and A. Keith Mant’s classic work ‘Taylor’s Principles and Practice of Medical Jurisprudence’ and H. W. V. Cox’s ‘Medical Jurisprudence and Toxicology’ to show that with modern propellants tattooing may be absent, though small flakes and threads of a gelatine-like substance may be visible on close examination, due to melted unburned cellulose-based propellant. Unfortunately, most police officers and doctors or forensic experts do not know such things or even this judgment.
In this important judgment, the High Court went on to pass verdict on many of the myths (such as the calibre of the weapon from the size of the entry wound) that we have busted above and which, unfortunately, had been regularly peddled as truth in thousands of cases across the country for decades.
The High Court was also very critical of the habit of the forensic experts giving a final opinion about the range at which a shotgun might have been fired from simply the shot pattern! The High Court held that the dispersal of the shot is a complex phenomenon depending on the ‘choke’ in the barrel, manufacture, condition and age of ammunition, deterioration due to storage, and deliberate tampering of the cartridge, etc. Any estimate of range based on a rule of thumb would be in serious error.
