On 24 October 2013, 23-year-old Kalwant and a 35-year-old Singaporean named Mohamad Yazid Bin Md Yusof were arrested at a multi-storey carpark at Woodlands Drive. The police officers from the
Central Narcotics Bureau (CNB) searched Yazid’s motorcycle and found six bundles wrapped with black tape, and these bundles contained not less than 120.90g of
diamorphine. Another three bundles containing around 60g of drugs were also found in Kalwant's possession after his arrest. Both Yazid and Kalwant were thus charged for drug trafficking. After his arrest, Yazid confessed during interrogation that on the instructions of his boss, known to him as "Boy Ayie", he was told to receive packages of diamorphine from Kalwant for the purpose of trafficking. However, Kalwant denied having knowledge of the diamorphine in his possession and claimed he was asked by his female boss through death threats to import the drugs, which he thought were not illegal narcotics. Kalwant also claimed that Yazid's testimony was untruthful since he concocted his statements to make himself able to positively get the chance to be certified as a courier. Still, the evidence showed that prior to passing Yazid the drugs, Kalwant had previous conversations with Yazid, in which he told Yazid about the drugs in the bundle, meaning he did have knowledge of the diamorphine he delivered. There were also traces of Kalwant's DNA on the packages (both on the inner and outer layers of the plastic), indicating that Kalwant had not only touched the packages but also re-packed the drugs. In July 2015, a year and nine months after the capture of Yazid and Kalwant, Yazid's boss "Boy Ayie", whose real name was
Norasharee Gous, was arrested by the police, which therefore led to the completion of the overall investigations in the case of both Yazid and Kalwant. Norasharee denied being Yazid's boss and claimed he had an alibi on that day he allegedly ordered Yazid to collect the drugs from Kalwant, and insisted he was innocent. On 1 June 2016, the
High Court, which heard the three men's cases in a joint trial a year later, rejected Norasharee's alibi defence and found him guilty of instigation and abetment of drug trafficking due to sufficient evidence and Yazid's testimony (which the court deemed truthful) against him. Kalwant's account was not accepted by the High Court and he was also convicted of drug trafficking. Since both Norasharee and Kalwant were not considered and certified as couriers due to their significant roles in the drug case, they were both
sentenced to death. On the other hand, Yazid, who was acknowledged as a courier, received a certificate of substantive assistance and was sentenced to
life imprisonment and 15
strokes of the cane for his crime. Norasharee and Kalwant both
appealed against their sentences. While the
Court of Appeal granted Kalwant's request to adduce further evidence to support his case in midst of dismissing his appeal, they agreed with the High Court's findings in Norasharee's case and thus rejected his appeal on 10 March 2017. With reference to the 1994 appeal ruling of
Chin Seow Noi v Public Prosecutor, the Court of Appeal upheld that the co-accused's testimony can be used as evidence to determine a person's guilt under the law while they rejected the appeals, though they emphasised on the need for caution to use the co-accused's testimony to determine a person's guilt due to the accompanying risk of false incrimination by the co-accused, and the conviction of a person on such grounds should be done with satisfaction that the person is guilty after considering every factor and incentive of the case.{{cite web|url=https://www.elitigation.sg/gdviewer/s/2017_SGCA_17 ==Death row==