‘Principle of Probability’ in Drug Case Involving Altered Police Notes

In a recent judgment, the Court of Appeal examined the principle of probability in a narcotics trafficking case, where alterations in police records and the lack of explanation for procedural irregularities raised serious doubts about the prosecution’s case. The case involved the arrest of a three-wheeler driver allegedly in possession of heroin, based on information received by narcotics officers.

According to the facts presented, officers from the Police Narcotics Bureau acted on specific information that a person was transporting heroin in a three-wheeler near De La Salle Junction. The tip was received by one officer at 12:40 p.m., and another senior officer was informed at 12:50 p.m. However, despite the urgency indicated by the informant, the officers left the Bureau only at 1:40 p.m., reaching the site around 2:10 p.m. Notably, the court observed that the time of the original note (12:20 p.m.) had been overwritten to reflect 12:40 p.m., raising concerns about the credibility and authenticity of the record.

Upon intercepting the vehicle, officers claimed to have found a brown substance suspected to be heroin in the driver’s pocket. The driver was arrested and later convicted by the High Court and sentenced to life imprisonment. However, the defence argued that a second person was present in the vehicle and had fled when the police signaled it to stop a version not properly addressed in the High Court judgment.

The Court further noted that the trial judge had misinterpreted the defence’s position, failing to give it due consideration. Additionally, the defence brought to the court’s attention that the same narcotics officers involved in the raid were later arrested on allegations of possessing heroin themselves, suggesting a possible manipulation of evidence.

“…Police officers’ notes are frequently regarded as critical forms of evidence, particularly in criminal proceedings. Even minor alterations to these records can raise concerns regarding the credibility of the documentation and the intent. As a result, most law enforcement institutions implement stringent policies that regulate how and when officers may amend their notes. In absence of any plausible explanation, an alteration, if highlighted, definitely affects the integrity of the investigation conducted by the police. Therefore, disregarding the highlighted time alteration has caused great prejudice to the Appellant…” 

“…The burden of proof is usually on the person who brings a claim in a dispute. It is often associated with the Latin maxim semper necessitas probandi incumbit ei qui agit, a translation of which is: “the necessity of proof always lies with the person who lays charges.” The learned defence Counsel brought to the notice of this Court that the officers engaged in the raid were later taken into custody on allegation of carrying Heroin. Hence, the allegation that there is a possibility that they had only produced a small quantity of Heroin and had concealed the rest.  Law enforcement institutions are entrusted with a diverse set of rules and regulations that must be followed in order to maintain a high degree of integrity within police departments and to prevent oversights. Where this does not function well, law enforcement officers may become prone to careless behaviour and unlawful activities (Handbook on Police Accountability, Oversight and Integrity- Criminal Justice Handbook Series)…” – Justice P. Kumararatnam

“A criminal case has to be proved beyond reasonable doubt. Although we take serious view in regard to offences in relation to drugs, we are of the view that the prosecutor should not be given a second chance to fill the gaps of badly handled prosecutions….” – Mohamed Nimnaz V. Attorney General CA/95/94  

Case No: CA/HCC/0039/2023 [Decided on 29.04.2025]

Before: P. Kumararatnam, J.  and    K. M. G. H. Kulatunga, J.