[13][14][15] In July 2019, Thuraisingam represented former property agent Teo Ghim Heng, who was charged with the murders of his pregnant wife Choong Pei Shan and their daughter Zi Ning at their Woodlands flat during the final week before the Chinese New Year of 2017.
Thuraisingam argued in the trial that Teo was suffering from major depressive disorder which impaired his mental responsibility during the commission of the offences, and he also put up the defence of sudden and grave provocation, since Teo recounted he was arguing violently with his wife over their precarious financial situation and Zi Ning's overdue school fees before he used a towel to strangle both Choong and Zi Ning.
Thuraisingam presented evidence of Ridzuan having low IQ and intermittent explosive disorder among several psychiatric disorders to support his client's defence of diminished responsibility, and made arguments to create reasonable doubt over whether Ridzuan had knowledge that his scalding of his child (not named due to a gag order) would lead to the boy's death.
Despite Thuraisingam's failed efforts to reduce the charge, he successfully argued for Boh to evade the death penalty and he was instead sentenced to lifetime imprisonment on the grounds that he did not exhibit viciousness or blatant disregard for human life, and that the murder itself was not premeditated in the first place.
[28] From September 2020 to December 2020, Thuraisingam and his firm associates Chooi Jing Yen and Hamza Malik represented a Bangldeshi painter on trial for killing his Indonesian girlfriend.
[29][30] However, Ahmed's defences were rejected, and he was therefore convicted of murder under Section 300(a) of the Penal Code and sentenced to the mandatory death penalty in December 2020.
[33] Thuraisingam and his colleague Suang Wijaya were both the defence counsel of Muhammad Salihin bin Ismail, a Singaporean charged with the alleged murder of his four-year-old stepdaughter Nursabrina Agustiani Abdullah (nicknamed Sabrina) in September 2018.
[36] In 2017, Thuraisingam was brought to court by Lucien Wong, the Attorney-General, for allegedly scandalising the judiciary when he wrote a poem, titled Our Five Stars Dim Tonight, critical of the death penalty hours before the execution of drug trafficker Muhammad Ridzuan Md Ali, whom he had represented.
A disciplinary tribunal appointed by Sundaresh Menon, the Chief Justice, held that Thuraisingam had not intended to attack the judiciary in his poem, which was found to be in contempt of court.
[45][46] In 2016, Thuraisingam received the Legal Assistance Scheme for Capital Offences award from Sundaresh Menon, the Chief Justice of Singapore, for his work in defending accused persons in death penalty cases.