Role of Informants & Probability in Criminal Cases

The Court of Appeal recently scrutinized the role of informants in criminal investigations, noting the inherent challenges in ensuring the reliability of such information. In this case, the police acted on details provided by a informant, who claimed a person had purchased heroin from Maligawatte and was traveling to Awwalsaviya Road in a green three-wheeler. 

The prosecution alleged that heroin was discovered during the raid, implicating the accused. However, the Court of Appeal identified critical gaps in the evidence, including the failure to establish an unbroken chain of custody and the lack of definitive proof linking the accused to the recovered contraband. Consequently, the court determined that the prosecution had not satisfied the burden of proof and acquitted the accused.

The court reiterated the importance of the probability test in criminal proceedings, requiring evidence to meet the standard of proof beyond reasonable doubt. 

“..The role of probability is pivotal in persuading the judge on specific points, as higher probabilities increase the likelihood of the judge being convinced. Probability plays a crucial role in criminal investigations, aiding in the evaluation of the relevance of different types of evidence. In order to accuse someone “beyond reasonable doubt,” it is essential to possess substantial evidence. To achieve this, certain assumptions must be made to draw conclusions. The likelihood of these assumptions being accurate is precisely termed the principle of probability in legal contexts….” – Justice P. Kumararatnam

“…. It must be mentioned here that the utilization of informants in Sri Lankan criminal cases are quite common. Law enforcement officers often use informants to attempt to fabricate cases against someone they believe is guilty of a crime. Hence, quite understandably, the Judiciary faces a dilemma and it becomes quite an arduous task when it comes to verifying the reliability of an information….” – Justice P. Kumararatnam

CASE NO: CA/HCC/0172/2019 [Decided on 05.12.2024]

BEFORE : Sampath B. Abayakoon, J. P. Kumararatnam, J.