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  • Digvijay Sahni

Sniffing the “Admissibilty” of Sniffer Dogs: A Comparative Analysis


A common procedure and technique which is often resorted to by the investigation authorities are to deploy sniffer dogs/ tracker dogs. These canines are well-trained and better equipped to track the accused and bring him to justice through their faculties and sensory powers. However, there has been always a reluctance and a sense of apprehension on the part of the judiciary to treat such evidence as admissible in law. Prima facie, the judiciary, and legislature are of the view that the guilt of the accused shouldn’t be determined through these canines’ inferences. On the other side, the courts abroad have adopted a more holistic and pragmatic approach where they treat such evidence as good and admissible in law and it is a general and common practice of theirs to convict a person based on such evidence. This article makes a case here that the courts must frame appropriate guidelines to acknowledge the faculties of these well-trained canines as evidence.

Necessity for Carving out a Provision in the Indian Evidence Act 1872

It is often seen that the courts perceive investigation carried out by authorities through contemporary mechanisms (involving scientific methods) in tune with the well-accepted principles and norms. The scientific methods such as lie-detection, narco-analysis, polygraph tests, etc. often retorted to by the agencies involve the collection and analysis of the reactions and responses of the accused which are then adduced and produced as evidence before the court. Though these tests have been held to be constitutionally valid by the apex court, there is a failure to recognize the inherent frailties, these tests might pose and cause a hindrance in the efficient and effective working of the criminal justice system. The Gujarat High Court mentioned that it is often perceived that when a person speaks the truth, the test reports it as a false response (false positive) and when a person lies, the machine reports that the person has spoken the truth (false negative). This happens as a person under examination can control his anxiety and emotions, hence, deceiving the examiner. Furthermore, such tests are subject to the consent of the accused and if conducted without obtaining his prior consent, then it would cast doubt on the prosecution case. It is at this juncture that the evidence of a sniffer dog could come as an aid as such dogs are carefully chosen based on pedigree and given special training, which should act as a reasonable ground in setting and endorsing a particular standard for accommodating such evidence.[i]

With the rampant use of canines, it becomes necessary to ponder upon whether the interpretation of a dog’s behaviour could qualify as an expert opinion u/s 45 of the Act. Though there is no specific provision that gives admissibility to evidence given by sniffer dogs and considers it hearsay, the judiciary must step in and recognize such evidence carrying some probative value in the eyes of law. Moreover, in one of the cases, there was an attempt by the Bombay High Court to recognize and give credibility to such evidence, where it was appealed that the judiciary must take cognizance of the evolving modern mechanisms and appreciate such evidence. This approach is considered to be one tending in favour of evidence collected through the aid of sniffer dogs, as there is not an ounce of doubt where these dogs can be misled or deluded in contradistinction to other forms of evidence collected through modern gadgets, which can be easily manipulated, and tampered with. Additionally, such evidence can come as an aid to lend corroboration to other pieces of evidence produced on record, as these dogs undergo rigorous training and exercises over a period of time, which make them proficient in detection.

The Kerala High Court[ii], again by mentioning the special capabilities of the tracker dog, and its prominent use in crime detection and investigations, held that the orthodox view regarding the inadmissibility of such evidence, should not be followed and the courts in appropriate circumstances should consider it. However, the probative value of such evidence would depend on the testimony of the handler and persons who witnessed its movements. There are several instances showcasing sniffers’ capability to hunt down criminals through scents, in turn proving their potential and calibre without any margin of error. The services of these canines also came as an aid in detecting drugs & psychotropic substances, and explosives which became the sole reason for their deployment by the USA and Afghan armed forces to carry out raids and patrols as it led to a surge in their discovery.

The orthodox view which tends to quiz the reliability and admissibility of such evidence was followed by the apex court in the mid-1969, where it highlighted three major problems; firstly, a dog himself can’t go into the witness box and give his statement on oath and hence, subject himself to cross-examination, secondly, life and liberty which form the core of Constitution shouldn’t merely depend upon the faculties of a canine, and thirdly, accepting such evidence as admissible as per the rules of evidence will inevitably obsess the jury to rely on such evidence in every case.

In another such case, the Supreme Court expressed its reluctance to rely on the evidence of a tracker dog due to the error in misjudging smells, mistaken tracking, wring interpretation of the dog’s behaviour by its master, and little knowledge about the faculties of such dogs with which they track and hunt down criminals. The unavailability of proper scientific research on the accuracy of their capabilities also worries the courts to deploy the services of these canines, as the judicial framework in the nation isn’t well-equipped to accept such evidence. The investigating agencies at best can rely on the services of these canines for the purposes of search & seizure and other similar purposes; an approach which has till date clouded the judiciary and prevented it from opting for a pragmatic view of collecting evidence, especially in a society that has seen rapid technological advancements.

Position in Other Jurisdictions

The second review of the New Zealand Evidence Act 2006 makes a provision, u/s 25, for the admissibility of an opinion given by an expert person. Expert evidence, as defined u/s 4(1), is evidence given in the form of an opinion by a person who possesses specialised knowledge or skill in respect of a particular subject matter. By placing reliance on the opinion of the experts, where the conviction was based on the evidence collected by deploying the faculties of canines, the court of appeal in R vs Lindsay[iii], found it to be satisfactory as the handler was fully aware of what his dog was thinking at the relevant time. The court also opined that there are certain safeguards in place and it is only when the dog and its handler (giving evidence on his behalf) are fully qualified and trained, such evidence would be acceptable. It is interesting to note here that despite admitting such evidence as good in law, it lays an onus on the trial courts to frame suitable safeguards and guidelines which will differ from a case-to-case basis.

In the United States, Rule 702 of the Federal Rules of Evidence, provides for statutory recognition to an opinion/ testimony given by a person who is an expert in the relevant fields which will inevitably help the judge to understand the evidence and determine a fact in issue. However, the pertinent question of whether such testimony is admissible or not came up before the court in Daubert vs Merrell Dow Pharmaceuticals, Inc.[iv], where the court devised certain guidelines and ruled that a testimony that enables the judge to understand the fact in issue and which furthers the scientific knowledge, will be admissible. The testimony given by a handler of the sniffer dog is based on its behaviour, which enables a judge to understand the issue and connect a various chain of events. Further, the reliability of dogs[v] can be demonstrated through the training and certifications it has received, their previous success rate in tracking down scents, their ability to discriminate between similar smells, etc. All these factors will play a great role in adducing the sniffer dogs’ evidence as competent, admissible, and relevant in law.

Concluding Remarks

A critical appraisal of the position in India highlights that neither the legislature nor the judiciary has taken appropriate measures to frame suitable guidelines to attach admissibility to the evidence of a sniffer dog. While the developed jurisdictions across the globe have taken steps to admit such evidence and framed suitable guidelines, the Indian courts must also materialise such an approach, and not exclude it by terming it as hearsay. The uniform approach adopted by the courts internationally can come as an aid in framing appropriate guidelines and devising circumstances where such evidence could be recognised and admitted. The courts can take cognizance of how the tracking was done, the history and the success rate of the dog, lack of discrepancy in the statements of the handler when subjected to cross-examination, & what is deposed by him panchnama, etc. Not to mention that the courts should be cautious, however, with the lacunas in the scientific methods of collecting evidence which often quizzes their admissibility, and their probable misuse, the faculties of canines should be put to use.


[i] R vs Kang Brown, [2008] 1 SCR 456.

[ii] Bhadran vs State of Kerala, 1995 CriLJ 676.

[iii] [1970] NZLR 1002.

[iv] 509 U.S.579, 113 S.Ct. 2786 (1993).

[v] Terrell v State of Maryland 239 A 2d 128 (1968).

This article has been authored by Digvijay Sahni, a third-year student at Maharashtra National Law University, Mumbai. 


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