Crime Scene Management by Forensic Experts

- Dr. B.K. Mohapatra, Dr. Kamal Chauhan 

U.S. Thakur & Alka Anand

 

        

Resolution of a criminal case is perfectly co-related with strategic evidence collections with greater accuracy from the scene of offence. It requires a patient, calculative and careful effort to collect substantial linking evidences to establish the crime in the court of law at beyond reasonable doubt. With the criminal activities getting modernized in recent years, the Crime Scene Manager too required to plan out accordingly regarding the precautions and strategies that are needed to be taken care of before proceeding to the scene of crime for collection of evidence.

 

 

1. Nature of crime:

 

The work schedule of a Crime Scene Manager is dependant on the nature of crime occurred. Different natures of crimes demand different procedures and precautions of scientific evidence collection. Crimes can be of various natures like _

 

· Biological offences

 

· Explosions

 

· Chemical offences

 

· Mass disasters

 

· Economic offences

 

· Cyber crimes etc.

 

In each of these cases, planning shall be different almost in all stages starting from the construction of the team of experts. Further, the demands with relation to the scientific equipments to be carried to the scene of crime, nature of chemicals and nature of transportation means of scientific evidences to the laboratory shall change. The Crime Scene Manager requires to organize the things suitably before proceeding to the scene of crime. In most of the cases, the crime scene requires a multi-disciplinary examination like a case of biological offence could also require expertise from the disciplines like Fingerprints, Ballistics (if fire-arms are involved),

 

2. Area selection:

 

The probable areas where linking evidences at the scene of crime could be found is to be determined by the Crime Scene Manager before getting into action of exploring the scene of crime. This can best be drawn by thorough consultation with the Investigation Officer as well as the local witnesses. Understanding the history of the crime helps to a great extent to determine the probable areas where search operations can be operated. Further, logical calculations of areas to be examined are to be drawn by the Crime Scene Manager for deriving circumstantial evidences at the scene of crime. For example if a crime occurred in a house the logical calculations can be the bath-rooms, dust-bins, ash trays, backyards of the house etc. Because after committing the offence, the suspect could have moved to the bathroom for washing, could have thrown certain evidences in the dustbin, could have left the cigarette butts in the ash tray or could have thrown the weapons in the back yard of the house. The selection of area of search once again varies with the nature of crime. For example, in case of explosion and ballistics related crime, the entire shock area and the probable path of ricochet are of great interest from investigation point of view. Effective area selection at the scene of crime also plays an important role with comparison of control samples with the evidence samples as it very frequently happens in cases pf physical examinations like matching of control soil samples with the evidence soil samples.

 

3. Protection of evidence from further destruction:

 

In a country like India usually the public reaches the scene of crime before the experts reach the spot if it is assessable. At the same time India being a hot and humid country, degradation of biological chemical evidences occurs very fast. In a situation like this, the first and foremost step of a Crime Scene Manager should be to protect the available evidences from further contaminations and degradation. The step-wise precautions to be taken in this direction are:

 

(i) Suspected area must be cordoned off and protected from public interference.

 

(ii) Suspected areas to be photographed thoroughly.

 

(iii) Document any people entering the area.

 

(iv) Not to use phones or bath-rooms in the scene area.

 

(v) Not to eat, drink and smoke in the scene area.

 

(vi) To mark the areas having maximum probability of obtaining evidence sample properly.

 

(vii) Selection of non-contaminated areas for obtaining control samples.

 

(viii) Provide protection to the available evidence samples from environmental hazards like heat, sunlight, water etc. as and when possible.

 

(ix) Document the total area of interest with respect to area volume, identifying points, distance from the crime scene of offence etc.

 

4. To be well equipped:

 

Very often resolution of the crime cases depend upon the results obtained from analysis of trace materials that were ejected as a result of interaction between the accused and the victim at the scene of crime. Collection of such trace materials require the involvement of sophisticated equipments, machineries and tools so that the complete material is recovered as well as the downstream applications with respect to these materials does not hamper. Common example of such equipments are powerful flash lights, poly lights, ultra violet scanners, high capacity magnets, vacuum cleaners etc. Application of all such equipments depends upon the nature of crime as well as position / place of crime. Further, use of machineries like big size earth movers, fire brigade machines, big size sieves etc. also become very important when evidences are to be searched from bigger areas and when the materials are disposed particularly under the earth or waste canals. The application of such machineries can be very well exemplified in cases like Godhra and Nithari Killings. In Godhra case, the evidences were buried under the earth and were to be excavated with the help of earth movers. The contents of forensic importance were sieved out for further analysis. In Nithari Killings case, as the evidences were disposed in the waste drains (Nallahs), the contents of the drain were removed with the help of earth movers, then washed with flush water from water canons of fire brigades and contents of forensic importance were sieved out for further analysis. Similarly involvement of sophisticated macro as well as micro tools is also required for absolute collection of evidence materials. Handy tools like magnifying glasses, needles, forceps, scissors, spatula, wash bottles, collection tubes / containers and kit boxes are to be properly organized by the Crime Scene Manager before proceeding to the crime scene investigation.

 

Micro / Sophisticated Tools

 

Micro / Handy Tools

 

5. Neat observations:

 

Focused observation of the Crime Scene Manager to the scene of crime reveals many secrets which may show some path for resolution of the case. The observation can be mechanized by using flash lights and magnifying glasses whenever required. The best way for observing the scene of crime thoroughly is to sub-divide the entire area of the scene of crime to small sectors and observe the entire area sector wise. Sectors can be made by drawing virtual geometrical lines.

 

6. Strategic calculations:

 

Probability of finding areas of evidence material is to be strategically calculated by the Crime Scene Manager. These calculations could be still stronger with analysis of the case history and

 

local enquiries.

 

The following are some main factors that influence the strategic calculations at the scene of crime for selection of finding areas.

 

(i). Environmental Factors : If a body or a weapon or some explosive materials etc are dumped in a canal having flowing water, calculation of the velocity of water flow, direction of flow, possible distance traveled by the evidence material with respect to the velocity of flow and its body weight, probable areas where the samples could have been accumulated are the major areas of calculation. Similarly in case of fire accidents, the flow of wind, direction of wind, environmental temperature are to be calculated logically to arrive at a point of area selection with maximum probability of collecting the evidence samples. Further, calculation of environmental factors is also required to determine the degree of degradation, destruction and disposal of the samples of forensic importance.

 

(ii). Movement factor : The shortest and safest distance that could have been used by the accused for disposal of the evidence samples are to be logically derived by the Crime Scene Manager during the investigation. There has always been a high degree of probability of trace samples like blood, explosives, footprints, prints of tyres of vehicles, and other physical evidences.

 

(iii). Feasibility factors : Feasibility of dumping particular evidence at a particular area is always to be calculated with great strategies. This avoids wastage of time and labour. Further feasibility is to be calculated to establish the causative factors of crime like if it is feasible to burn the area with petrol, kill so many people without using weapons etc. Feasibility study has always been a sensitive area of calculation for pin-pointed recovery of evidence samples.

 

7. Scientific collection and preservation:

 

The entire labour of planning and collection goes waste if the collection procedures of forensic evidence samples are not followed strictly. Validated scientific procedures of collection of samples must be adopted to ensure a productive result out of the analysis of the materials collected. Collection procedures varies greatly depending upon the nature of evidence samples from biological samples to physical samples to chemical and ballistic samples. However, the common precautions to be taken care of are as follows:

 

(i) Avoid contaminating the evidence area by not touching it with bare hands or sneezing and coughing over the evidence.

 

(ii) Use clean latex gloves for collecting each item of evidence. Gloves should be change between handling of different item of evidence.

 

(iii) Each item of evidence must be packed separately.

 

(iv) Blood stains, semen stains and other type of stains must be thoroughly air dried prior to sealing and packing.

 

(v) Sample should be packed in paper envelope after drying and should be clearly marked with case no, item no etc.

 

(vi) Stains on immovable surfaces (such as tables and floors) may be transferred with sterile cotton swabs and distilled water. Rub the stained area with the moist swab until the stain is transferred to the swab. Allow the swab to air dry without touching and pack properly.

 

(vii) Collect materials in sterilized bags / containers.

 

(viii) Avoid cross _ contaminations.

 

(ix) Collect separate evidence samples separately with proper documentation / markings.

 

(x) Precautions to avoid further degradation of samples.

 

(xi) Temperature controlled packing of temperature sensitive samples.

 

(xii) Control evidence samples must be collected when ever required.

 

Collection / Preservation of evidence samples

 

8. Documentation

 

The proceedings of a crime scene is to be documented properly. Documentation with respect to list of exhibits collected, control samples collected, mode of collection, quantity of collection , date and time of collection, witness of collection, environmental conditions during the time of collection etc are to be recorded which helps to a great deal during post collection analysis as well as in the court of law. Further proper documentation is also required for specialized samples collection procedures like the Biological sample collection formats and formats related to cyber as well as economic offences where the required forms are to be filled up as directed and to be recorded.

 

9. Forwarding to laboratory