Too Yin Sheong was born on 26 December 1971 in Malaysia. He was a secondary school dropout with a modest background, living with his mother and stepfather who were both permanent residents in Singapore. Before his arrest, Too worked as a manager in a karaoke lounge in Johor Bahru, Malaysia. He had a younger brother and two older sisters.

At the time of the crime, Too was 22 years old and moving between Malaysia and Singapore, frequently crossing the border for work and social visits. In October 1993, while in Singapore, he met 54-year-old Professor Lee Kok Cheong at a coffee shop in Dover Crescent. Professor Lee, a respected academic and head of the English Proficiency Unit at the National University of Singapore, lived alone and had a passion for Chinese antiques. He was known as kind and generous, although he kept a private life.

Lee took an interest in Too and befriended him, even inviting him over to his house. During their first meeting at Lee's home, Too became uncomfortable when Lee made physical advances. After this encounter, Too discussed the situation with two of his friends—Ng Chek Siong and a third man known only by the alias "Kim Beh."

On the evening of 12 December 1993, Professor Lee Kok Cheong was at home, preparing to receive guests. He had cooked food and served drinks for two visitors, believing it was a social gathering. Those guests were Too Yin Sheong and his associate "Kim Beh." Unknown to Lee, they had planned to rob him.

After being let inside without any forced entry, the two men tied Lee’s hands and feet and brought him into the master bedroom. According to Too's confession, Lee pleaded not to be harmed. Too claimed he left the room as "Kim Beh" retrieved an electrical cord and used it to strangle Lee to death. The victim was also stabbed during the attack, though the strangulation was the confirmed cause of death. Too insisted that he did not participate in the killing but admitted to witnessing it from just outside the room.

Once Lee was dead, the two men ransacked the house. They stole cash, jewellery, and Lee’s ATM card, which they later used to withdraw over S$3,400 and purchase more than S$3,900 worth of goods including clothing and jewellery. Lee’s body was left tied and face-covered on the bedroom floor, where it remained for two days before being discovered by police on 14 December 1993.

The murder shocked Singapore’s academic community. Professor Lee, described by colleagues as quiet and deeply intellectual, was found with his hands tied by telephone wires and his legs bound with a belt. His face was covered with a pillow, indicating an effort to conceal the brutality of the crime.

A massive manhunt was launched. CCTV footage showed three young men making purchases using Lee’s stolen card, and in 1995, a tip-off revealed the nickname “Nelson” as one of the culprits. That led to the arrest of Too Yin Sheong at the Woodlands Checkpoint on 23 December 1997.

Too was charged with murder the next day.

Too stood trial on 17 August 1998 at the High Court of Singapore. He was represented by defense lawyer Ramesh Tiwary, while the prosecution was led by Deputy Public Prosecutor Lee Sing Lit. During the proceedings, Too presented himself as a passive participant, arguing that the killing was carried out solely by "Kim Beh," and that his own role was limited to robbery. He claimed confusion and fear prevented him from stopping the murder.

However, the prosecution rejected his version, calling him a cold-blooded killer who knowingly allowed the murder to happen. They emphasized that the trio shared a common intent to rob Lee, and that silencing the victim was part of their plan. Too’s behavior after the crime—such as withdrawing cash from Lee’s account and going on a shopping spree—contradicted his claim of being remorseful or traumatized.

On 28 August 1998, Judicial Commissioner Chan Seng Onn found Too guilty of murder. In his ruling, the judge stated that even though Too did not physically strangle Lee, his actions and failure to intervene made him equally culpable. The judge pointed out that Too had a cool and calculated mindset and acted without remorse. He handed down the mandatory death sentence.

Too’s appeal was dismissed on 10 November 1998 by the Court of Appeal, which upheld the ruling that Too was a willing accomplice to a brutal murder

On 30 April 1999, Too Yin Sheong was executed by hanging at Changi Prison. He was 27 years old. On the same morning, another condemned man, Gurbajant Singh, was also hanged for unrelated drug trafficking charges.