Kalwant along with another man named Mohamad Yazid Md Yusof were arrested on 23 October 2013, and the alleged mastermind Norasharee Gous was captured two years later in July 2015, and all three of them were charged with drug trafficking.
Kalwant left school at age 17, and started working odd jobs as a waiter, a courier, a tour guide, and a truck driver.
[5][4] In 2011, Kalwant settled in Johor Bahru and he began to commute daily to Singapore, where he found a job as a mortuary worker at a local hospital.
[4] 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.
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.
[18] During the time Kalwant was incarcerated on death row at Singapore's Changi Prison, there were five other Malaysians, including Nagaenthran K. Dharmalingam, who were executed for drug trafficking since 2016.
[19] In May 2022, the ninth year of Kalwant's incarceration, there were pleas by Malaysian activists to send the Malaysian drug convicts back to Malaysia to serve their sentences, due to the financial issues taking a toll on the families of these convicts due to the legal fees and transportation fees of travelling from Singapore to Malaysia, which was compounded by the ongoing COVID-19 pandemic situation ever since 2020.
Despite the emotional toll the death penalty took on Kalwant and his family, his loved ones, including his father, sister and niece, unfailingly went to visit him at Changi Prison.
Kalwant's father, who did not give up working in order to pay for their transportation expenses, last visited his son in March 2020 before the COVID-19 pandemic broke out, and he passed away in May 2021, three months after he was diagnosed with terminal cancer.
At that time, Singapore was criticised by death penalty abolitionists for executing Abdul Kahar Othman and Nagaenthran K. Dharmalingam (the latter whose case was more controversial due to his alleged intellectual disability) just months before in 2022 also for drug trafficking, which made said activists more prompted to argue for the lives of Norasharee and Kalwant to be spared and commuted to life imprisonment instead.
[35] The Singapore Prison Service (SPS) responded to the queries of CNN, confirming that the capital sentences of Norasharee and Kalwant were carried out on the same day they were hanged, stating that both men had been accorded full due process and exhausted their appeals before both their death warrants were finalized.
[37] The European Union claimed that the death penalty was a "cruel and inhumane" punishment and showed their opposition to it, and condemned Singapore for executing both Norasharee and Kalwant.
[38] The human rights experts from the United Nations issued their statement which specifically addressed their condemnation towards the execution of Kalwant (Norasharee was not included), and they urged Singapore to revise their use of the death penalty through suspension of its practice and abolition, stating that drug offences did not constitute as one of the most serious offences by international standards and called the mandatory death penalty "an arbitrary deprivation of life" since it was imposed without taking consideration of the extenuating circumstances of each and every capital case.
On 9 July 2022, the Singaporean authorities issued a 24-month conditional warning towards the LFL member and lawyer Zaid Malek for having shared the misinformation, which were considered as a "contempt of court" under Singapore's laws.