On 5 May 1999, 43-year-old seaman Aw Teck Boon (区德文 Ōu Déwén),[a] alias Singapore Siao (新加坡笑 xīn jiā pō xiào),[b] was found murdered at Geylang after drinking at a nearby coffee shop.

[2] It was speculated that Aw was attacked and stabbed to death while he was sleeping at a Wushu association club, likely due to unsettled underworld conflicts.

According to his younger sister, Aw became independent and lived separately from his parents and siblings during his teens, and worked as a sailor for most of his life.

[6] Apart from his time on the ocean, Aw Teck Boon joined the Sio Kun Tong gang (affiliated with the Salakau)[c] during his younger years and he gradually rose through the ranks, and become a much-feared triad leader with at least 60 men under his wing,[7] in addition to five or six bodyguards beside him wherever he went.

Together, Aw and his wife had one daughter Wendy, who was born in 1995, and they lived at a one-room flat at French Road, Jalan Besar.

He was notorious for his bad temper and weakness in alcohol, and was noted to have flew into a violent rage and picked fights very often whenever he had too much to drink at the coffeeshops he frequented in Geylang and Beach Road, and he would offend people while he was heavily drunk.

[34] About 30 police detectives had attended Aw's funeral, not to pay respects but to maintain order and inspect for any suspicious people present at the wake.

The atmosphere of the funeral was reportedly tense; while there were people coming to pay condolences, others only turned up not because of friendship but out of reluctance in order to maintain respect for the late gangland chief.

One theory was that Aw had offended a lot of people with his bad temper and drunken fits (one of these included a dispute at a funeral),[40] and it provoked his rivals into attacking and killing him.

[43] After preliminary investigations, the police identified a prime suspect, a 38-year-old Singaporean citizen named Chew Tse Meng (alias Ah Say; 阿势 ā shì),[d] whose last known address was in Choa Chu Kang.

[46][47] Merely two months after Aw was killed, Singaporean crime show Crimewatch re-enacted his murder and it first aired on television in July 1999.

The police investigations revealed that within the two hours after the estimated time of Aw's murder, Chew boarded a taxi and left Singapore via the Woodlands Checkpoint and fled to Malaysia.

The list included Aw Teck Boon himself, while the other two were Tan Chor Jin and Roland Tan; Tan Chor Jin, nicknamed Tony Kia or "One-Eyed Dragon", was found guilty and hanged in 2009 for the fatal shooting of nightclub owner Lim Hock Soon in 2006, while Roland Tan, nicknamed "Mr Big", was wanted by Singaporean police for the 1969 unsolved murder of Lam Cheng Siew at Bras Basah, but he escaped prosecution by fleeing to the Netherlands and established an infamous drug trafficking syndicate Ah Kong, before he relinquished control of Ah Kong and relocated to Denmark, where he lived out his remaining years as a restaurant owner and died from a heart attack in 2020.

Aw's killing was also speculated to be the mark of decline of the phenomenon of gangsterism, and it was also coupled by the indefinite detention of older gang members without trial under the Criminal Law (Temporary Provisions) Act (CLTPA).