Forensic Necropsy of Wild Animals
–Harshit Saxena
UG Scholar, BVSc & AH- 5th Prof Yr.
CoVsc & AH, DUVASU, Mathura
Forensic or Vetero-legal necropsy of wildlife is of much importance in the era where crime against wildlife is increasing at steady rate and because protection of biodiversity is one among Sustainable Development Goals. It is duty of law to safeguard the interests of animals and levy proper punishment to accused once when a case is filed against crimes like hunting and poaching a detailed necropsy report prepared by a veterinarian gives a eminent evidence regarding the act of crime. Though development of discipline of forensic necropsy of wildlife is not much intense the extrapolation of procedures practiced in human forensics are applied. Though some forensic laboratories have developed their own standards to be used by wildlife officials to carry out procedures in light of Veterinary wildlife jurisdiction .
https://www.pashudhanpraharee.com/approach-of-veterinarians-to-vetero-legal-cases-in-field/
Purpose and Aim–
Main aim of forensic necropsy is to determine cause, nature, time of death of a particular animal. At the onset of any forensic examination it is important that that pathologist and person requesting the examination discuss what can be and what cannot be accomplished by necropsy.
Procedure–
- Custody of carcass and samples-
A forensic examination begins right from the crime scene where carcass of animal is obtained. The competent officer that takes custody of carcass must collect all evidence from site and submit them to pathologist along with carcass. The chain of evidence starting from enforcement officer to pathologist and back to officer must be under stringent protocol of confidentiality. The pathologist receiving the carcass must know the time of receiving of carcass along with subsidiary site evidences. The tag applied to carcass mentioning all necessary details should be retained till formulation of final report. Rest all samples- pathological, microbiological, toxicological collected must be properly labelled and kept under security. Evidences like bullets, poison etc found must be handed to enforcement officer for further investigation.
- Record Keeping
A major difference between an ordinary necropsy as done in wildlife disease diagnostic laboratory and a forensic necropsy relates to the completeness of records that are kept about the procedures and the results obtained. As most of the forensic cases do not reach in court on time taking months to years thus when pathologist is summoned to court for expert witness the details of necropsy are almost blurred. The only document prepared at the time of necropsy examination helps pathologist to ascertain his view.
Thus when a necropsy report (forensic especially) written must be completely detailed about-
- Complete history-
Circumstantial evidence and collection of evidence at crime. Determining proper identification of animal’s specie, sex, identification marks etc. If animal is digitally labelled by chip or so it must be retrieved and collected.
- Assigning unique number to every case is very important in record keeping. All the observation (necropsy, microbiological, histological, toxicological) must be clearly mentioned with the case number. Thus, when a report stated must clearly mention the characteristic condition of carcass and collection enquiry. Ex- Specimen A-44-146 and bearing the signature of enforcement officer was found as male cub received from (Submitter’s name) on (date) to which was a fixed a label with the other important information.
- The final necropsy report will form the basis of any investigation & proceedings that occur in court.
- Description of necropsy findings must be complete, clear and as far as possible phrased in non technical language that will be easily understood by the non technical medical person who will have to deal with them in court.
- When criteria like age, stage of life body condition is to be determined by necropsy examination it must be recorded together with the criteria used to establish the facts like dentition for age , skin colour for body condition etc.
- Outline, drawings prepared in advance or at time of necropsy are particularly useful for recording the location of lesions of traumatic wounds.
- Photographs– Pathologist must take photograph of intact carcass, body lesions, area of interest, location. Every photograph should contain information that clearly identifies the animal, the data, size, reference scale and identity of pathologist. For reference scale several cards can be made of different colour each symbolising a particular type. Pointers can be used to identify connection between lesions such as path of bullet through body.
- The record must highlight properly the organs that are examined or not examined they are described as negative and positive so as to tell the organ –
- Examined and found normal
- Not examined
- Abnormalities and lesions must be described as absolute values in centimeters or grams rather than those of relative terms like larger or smaller.
- The location of injuries and abnormalities must be recorded according to anatomical landmarks.
- Rough notes/ dictation must be made by pathologist to prepare necropsy reports with help of assistance original notes must be kept until all possible proceedings of court are completed.
- All reports, photographs, physical specimens, results of ancillary test must remain in custody of pathologist until taken by investment officer or court of law.
External Examination
- Veterinary forensic necropsy external examination reveals lesser compared to humans as in animals massive hairs plumage, pelage conceals much.
- Penetrating gunshot wound done by short or small calibre bullet are hard to identify.
- Any evidence of external blood exudate excreta foreign material should be recorded.
- Body should be visualised closely to identify marks of singed hairs, feathers and electrocution.
- Animal should be weighed prior to necropsy.
- As often wildlife carcass is found incomplete details of complete and incomplete portion must be well marked.
- Time of death can be written/ predicted by visualising Rigor-Mortis, studying entomology of insects on carcass and other parameters.
- In case of suspected gunshot wounds radiographs must be taken.
Internal Examination
- In forensic cases it is advised to fix carefully skin animals as first step of internal examination to expose hidden wounds.
- A herbivore or ruminant must be kept on left side down, horses on left side up, pig on ventral recumbency and carnivores on dorsal recumbency .
- Skinning should be done carefully as it may reveals any bullet lost in subcutaneous tissue or under skin.
- In Raptors hind limb should be skinned carefully to examine for Marks caused by leg holding traps.
- If trap injury suspected radiograph must be taken.
- Remaining forensic technique follows standard necropsy techniques and consists of systemic examination of positional relationship, size, colour, shape, texture of all organs including brain and spinal cord.
- All hollow organs must be opened to appreciate its lumen and content
- For examination of gunshot wound basic ballistic knowledge must be there.
- Tracing of path of projectile must be done.
- Entrance wound of gunshot are smaller and have inverted edges however exit wounds are larger and have everted edges.
- Relationship between separated found parts must be established by DNA extraction and comparison can be carried out.
- Bones often need to be cleaned in forensic necropsy to mark fracture and cut marks. If bones are cleaned of flesh by boiling they must be bind by cheese cloth and marked to avoid intermixing.
Specimens for Ancillary tests
The types of specimen collected at necropsy for subsequent examination will depend on circumstances of particular case.
- Ancillary tests used commonly in forensic work include histology, toxicological analysis, ballistics and recently DNA tests to establish identity of individual animals.
- Specimens collected for such analysis must be collected as per the standards of the laboratory from which tests to be done. Thus amount of sample, container in which they must be kept, preservative all must be proper.
- Sterile free samples should be collected for DNA microbiological and toxicological analysis.
- Bullet should be traced inside body with radiographic examination and must not be handled with metal forcep but with gloved hand and washed to remove blood and tissue under flowing water over a strainer.
Shipping Specimens to other Laboratories
All analytical procedures may not be available locally and specimens may have to be sent to other laboratories. It is important to establish in advance that a laboratory chosen has experience of forensic/legal analysis, understands chain of custody and analytical scientists involved are suitably qualified to serve as witnesses. Samples that are hazardous must be labelled properly. Specimens individually labelled are kept in inappropriate containers are further placed within box, envelope or freezer chest that is sealed carefully with tape, sealed and marked clearly as evidence.
It is useful for pathologist to sign across tape so that the consignee is assured that parcel was unopened when received. As paper with same signature on top kept inside box to match both.
A covering letter, tests requested must be placed in envelope labelled as documents that is attached with tape over box. The laboratory must be informed about date of shipment and required data.
Summing up, forensic necropsy implies detailed procedure as compared to routine method and as wildlife crimes cause stringent action if accused is proved to be guilty no casual way is allowed in examination. Data should be lucid & readable by non medical people in court. Cause of death should be concluded in transparency to avoid repeated call of pathologist by court to describe the case. Honest and skillful pathologist not only do justice with his profession but with these creatures living quietly in their habitats and becoming victim of humans now and then. A proper wildlife forensic necropsy really aids in welfare works towards wildlife.
