Sciencedoze: Science, Education and Technology

The Fingerprint Bureau of India, also known as Central Fingerprint Bureau (CFPB) was set up in Kolkata in 1955 under the administrative control of the Intelligence Bureau (IB).  But, In 1973, the administrative control was transferred to CBI and again in 1986, the administrative control was finally given to the newly formed National Crime Records Bureau (NCRB) located in R.K Puram, New Delhi. Functions of Fingerprint Bureau of India 1. The main function of FPB is to maintain the fingerprint data of Indian and Foreign criminals. The record of foreign criminals is sent by the Interpol Division of CBI. 2. It also examines the questioned fingerprint impressions referred by central Govt. departments and other Govt. of India undertakings. 3. It also imparts training in fingerprint science to police and non-police personnel of the state govt. and personnel of foreign countries under the 'Technical Co-operation Scheme'. 4. It also conducts the All India Board examination every ye...

What is DNA fingerprinting? DNA fingerprinting is a laboratory technique that is used to determine the identity of a person using a unique pattern in the minisatellites of the genome of an individual. It was first invented in 1984 by Sir Akec Jeffreys after he realized that we can detect variations in human DNA based on these minisatellites. On average, about 99.9% of DNA between two individuals is the same, the remaining 0.1 % makes the person unique. DNA profiling, DNA testing, DNA examination, Genetic profiling, and Genetic fingerprinting are branches of DNA fingerprinting. Following is the complete process of DNA fingerprinting: RFLP (Restriction Fragment Length Polymorphism) The first step of DNA fingerprinting is to extract DNA from the biological fluid of human-like blood, buccal swabs, etc. Then molecular scissors, also called restriction enzymes are used to cut the DNA into thousand pieces of different lengths. These pieces of DNA are now separated using gel electrophoresis...

Prof. Jan Evangelista Purkinje The history of fingerprint science dates back three 3000 years as it was first used in Chinato to sign legal documents. Then, In 1823 Prof. Jan Evangelista Purkinje published a thesis describing the friction ridge patterns and classifying fingerprints into Nine categories. Sir William Herschel In 1858, An English civil servant Sir William Herschel posted in Bengal, India, started the practice of recording handprints of native Indians to sign the contract. This, greatly prevented the cheating and impersonation among native Indians to sign the contract. But, William Herschel did not publish any of his findings. Dr. Henry Fauld In 1874, Dr. Henry Fauld , a Scottish physician working in a hospital in Tokyo, Japan, published his theory on the potential use of fingerprints for personal identification. In 1880, Dr. Fauld suggested that skin ridge patterns can be proved important for the identification of criminals. He also published his findings in Boo...

What are Different Types of  Fingerprint Patterns? 1. Arches Arches are found in approx 5% of the recorded fingerprints. In an Arch pattern, ridges enter from one side travel to the other side, and lift slightly at the center of the pattern (like a wave) finally exiting from the opposite side.  Based on the nature of Arches they are further divided into two types i.e. Plain Arch and Tented Arch. (a) Plain Arches Plain Arch is the simplest pattern among all fingerprint patterns. In a plain arch, the ridges enter from a side (say left) and flow to the opposite side (Right) by making a small rise at the center like a wave. They don't have any core deltas but they do have numerous ridge formations like ridge endings, bifurcations, dots, and islands. (b) Tented Arches In this type of Arch, most of the ridges enter from one side and flow towards the opposite side by making a definitive angle ( 90 degrees or less ) or standing straight at the center of the pattern and finally exitin...

(a) Presumptive Test 1. Phenolpthalein Test (Kastle Meyer Test) Place a small portion of the suspected bloodstain, such as a cutting, swab, or extract, onto a piece of filter paper. Two or three drops of ethanol are added to the stain. Add two drops of the prepared phenolphthalein solution to the stain. After ensuring that no color develops during this waiting period, 2-3 drops of 3% hydrogen peroxide are introduced to the stain. The emergence of a vibrant pink color signifies a positive result for peroxide activity, indicating the presence of hemoglobin. 2. Leuomalachite Green Test (LMG) A small curring, swab, or extract of the suspected bloodstream is placed on filter paper. Add leucomalachite green solution to the stain. If indicate green color appears then it gives a positive test for the presence of blood. 3. Alder Test (Benzidine Test) It is the oldest method for the detection of blood which was developed by Alder in 1904. It produces dark blue color in the reaction of blood...

What is Ballistics? Ballistics is a branch of science that deals with the propulsion, flight, and impact of projectiles on the target. The term "Ballistics" finds its roots in the Greek word "Ballein," signifying "to throw" or "to project." It is Colonel Godard who first coined forensic ballistics. He used the systematic study of firearms and ammunition for investigation and justice. Types of Ballistics Ballistics is divided into three major types: 1. Internal Ballistics Internal Ballistics is the branch of ballistics that deals with the study of the projectile inside the barrel of the firearm that is from when the firing pin hits the primer to the time the bullet exists the barrel from the muzzle end of the firearm. It is also known as Initial or Interior Ballistics. Internal ballistics helps in linking the projectile with the firearm by studying scratch marks on the projectile, velocity of the projectile, defects in the barrel, Erratic ...

1. Energy Considerations A projectile that needs to be put in motion needs energy. Whether it is throwing stones into the atmosphere or flying arrows. In both examples, human (mechanical) energy is involved. But, in the case of a firearm, to put a projectile (bullet) into motion, chemical energy is used which comes from the burning of propellants. 2. Propellents Gunpowder is the most commonly used propellant in modern firearms. Propellents have unique characteristics in that they burn rapidly releasing large volumes of gases at high temperatures. These gases produce high pressure which put the projectile into motion. It is noted that only a little portion of this energy gets converted into kinetic energy of the projectile, the rest energy is wasted and dissipated as a muzzle blast. 3. Initiation Upon squeezing the trigger, the firing pin impacts the primer, initiating the ignition process. The primer then compressed and explodes that provides a frame that ignites the propellents. If ...

Securing the scene of the crime A crime scene has certain physical evidence which forms the basis to link the victim, suspect, and crime scene. Anyone entering the crime scene can contaminate these pieces of evidence which can change the original crime scene.  Thus, it is necessary to secure the crime scene not only from the onlookers, press, etc but also from inexperienced police personnel. 5 steps to secure the crime scene If the victim is dead then its body should not be removed but instead left undisturbed until the proper documentation is done. If the victim is still alive then medical assistance should be provided as soon as possible to save a costly human life. The crime scene should be cordoned off with "crime scene do not cross" tapes or any physical barriers like barricades, vehicles, etc. Once the cordoning is done, two or three officers should be deployed around the barrier to prevent unauthorized entry of people especially curious onlookers. A contamination l...

What is Forensic Chemistry ? Forensic chemistry is the branch of forensic science that deals with the analysis of unknown chemical substances found at the scene of the crime like explosives, drugs, accelerants, poisons, etc. Forensic chemistry helps to link these substances with the suspect through different analytical techniques like HPLC, GC-MS, AAS, IR spectroscopy, FTIR, NMR Spectroscopy, etc . Moreover, the nature of these chemicals can also be identified by performing presumptive tests at the scene of the crime itself. Application of forensic chemistry In the arson case investigation, the potential accelerants used in arson present on the debris can be analyzed through techniques like gas chromatography-Mass spectroscopy. Gunshot residue present on the scene of the crime or the clothes of the victim/suspect can be analyzed under the scanning electron microscope. Forensic chemists examine evidence like blood stains, and urine to find traces of drugs, toxins, or poisons. Paper or t...

1. Classification based on size and handling mechanism 1. Handguns Firearms that are short and compact and can be held in one hand. They have generally short barrels. They are further classified into two types: (a) Revolver A revolver is a short barrel firearm having a cylinder at the rear of the barrel. This cylinder has various chambers in which the cartridge is placed. When the trigger is pulled, the hammer facing one of the chambers of the cylinder strikes the primer of the cartridge, and hence the bullet fires. (b) Pistol A pistol is also a short barrel firearm having a magazine loaded with bullets. The magazine has a spring beneath it which push the new cartridge into the firing chamber after the previous bullet is fired and the process keeps going on till the magazine got empty. Pistols are available in all calibers ranging from 5 to 12 mm. 2. Shoulder Gun Firearms that are long barrels and relatively bigger and fired only with the assistance of a shoulder are known as should...

The history of firearms started in the 9th century when the Chinese accidentally developed gunpowder. After this, the gunpowder spread to the whole world from the middle east to Europe and Africa. So, here is the development of firearms since the 13th century. 1. Hand Canon (1271-1368) It was first used by the Chinese Yuan dynasty in 1300. These hand canons were made of bamboo and the projectile along with gunpowder was loaded through the muzzle end. Also, a small hole is placed at the breech end which is ignited that causes an explosion realizing the projectile from the canon. Hand cannons required much strength to hold for better stability. 2. Match lock (The early 1400s) In the matchlock firing mechanism, a wick was placed near the propellent/primer through the breech end of the weapon, and when that wick is ignited it causes a spark in the propellent which burns rapidly and pushes the projectile into a forward direction. The main disadvantage of this system is that it can'...

Following are the Factors affecting the poisoning: (A) Factors pertaining to the substance 1. Dose The more the quantity of poison, the more severe will be the toxic effects. But it is not necessary all the time, sometimes larger doses result in vomiting, thus reducing its intensity. But in the majority of cases, more dose will produce more toxicity. 2. State Gases and vapor act more rapidly than liquid poisons. Whereas, liquid poisons act more rapidly than solid poisons. And in solid poisons, fine powdered solid poisons act more rapidly than coarse ones. Thus, the state/form of poison directly affects the effect of poison. 3. Chemical combination The action of poison depends upon the chemical combination that will alter the solubility of the poison in the body. For eg, AgNO₃ and HCl are both strong poisons, but when combined, form or, an insoluble salt of AgCl which is harmless. 4. Mechanical Combination The action of poison is considerably altered when combined mechanically wit...

Any substance (solid, liquid, or gas) that if introduced to a living body, produce ill health or death is called poison.  So, the following are the mode of action of poisons: 1. Local Action In local action, the poison when come in contact with a particular body part then produce harmful effects at the site of contact. For eg, strong acids and alkalis cause irritation and inflammation at the site of contact. 2. Remote Action In remote action, the poison develops toxicity at a particular designated site of action/target irrespective of the route of administration. For eg, Mercury vapors if inhaled produce neurotoxicity. 3. Remote-Local action (Systemic Action) In systemic action, the poison produces toxic effects at the site of administration as well as at the particular target organ to develop their toxic effects. For eg, a Snakebite affects the bitten tissue as well as the central nervous system. 4. General Action In general action, the absorbed poison evokes a response from a wid...