On 1 July 2007, 29-year-old Manap Sarlip was found murdered outside his flat at Whampoa, Singapore. The police investigations led to the arrest of the killer, 17-year-old Muhammad Nasir Abdul Aziz, and Manap's 24-year-old wife Aniza Essa, who ordered and manipulated Nasir to kill Manap. Both of them were charged with murder and abetment of murder respectively. It was revealed that Aniza, who was in an unhappy marriage with Manap due to his abusive behaviour, had an affair with Nasir, who fell deeply in love with her; therefore, she instigated Nasir to help her kill her husband under the pretext that they would end up together without him. With her depression taken into account, Aniza was sentenced to nine years' imprisonment after pleading guilty to manslaughter. As for Nasir, he was found guilty of murder but was imprisoned indefinitely under the President's Pleasure since his age of 17 prevented him from receiving the death penalty under Singaporean law.

Aniza Essa, born in 1982, studied up to Secondary 3 and dropped out. In September 2001, at the age of 19, she married her husband, Manap bin Sarlip; they had one son in 2006. Manap's eldest child from his first marriage, also a son, stayed with them. Manap worked as a disco jockey in a discotheque; he had been imprisoned for 21 months for desertion of national service, which he had been serving in the Singapore Civil Defence Force (SCDF). The marriage between Aniza and Manap was unhappy; Manap was abusive towards his wife, who had to work two jobs during his absence to support herself and the two children. The abuse had gotten worse after Manap's release from jail on 15 August 2006. By 2006, Aniza was working at a pub; there, she met a 16-year-old Nasir, who would eventually become her lover.

Aniza's colleague and lover, Muhammad Nasir Abdul Aziz, was born in September 1990; he had an older brother named Muhammad Khamil. Nasir's mother abandoned his family while he was an infant, with his parents divorcing when he was two months old. Nasir was raised by his aunt during his childhood. He left school in Secondary 3 to work and support his family; he took care of his father, who was suffering from poor health, and helped tend the father's shop. In 2006, Nasir met Aniza at the pub she was working at, which he frequented; the two began an affair after he became a bartender in February 2007. He was said to have fallen deeply in love with her, whom he regarded as the "most beautiful" woman he had seen.

By mid June 2007, Aniza could no longer tolerate her husband's abuse, and she occasionally would confide to Nasir about the unhappiness and depression she suffered under Manap's abuse. Although Nasir advised Aniza to divorce her husband, Aniza stated she was afraid of Manap coming to harass her after the divorce and she also stated Manap would never consent to her request to divorce him.

Eventually, Aniza formulated a plan to commit the murder of her husband, and she told Nasir to help her kill Manap. She also threatened to leave Nasir and entrust the task to her former boyfriend, should Nasir reject the offer, which she described as the only one chance for Nasir to show his love for Aniza. Afraid of losing Aniza, Nasir agreed to do the task. Initially, Nasir made the first attempt to assassinate Manap but after he saw a neighbour approaching Manap nearby his flat, Nasir had to abandon the task, and therefore, after further discussion with Aniza, Nasir contacted a friend nicknamed "Saigon" to help him find a hired professional killer to help do the job, but by the deadline of 29 June 2007 agreed upon by Nasir and Aniza, Saigon did not find one and he did not respond to Nasir's messages or phone call.

After failing to find a hired hitman to go after Manap, Nasir was faced with Aniza's insistence to commit the murder, and he promised to do so personally by the end of the month. On the night of 1 July 2007, Nasir wore a helmet and armed himself with a knife, and he waited outside Manap's matrimonial flat in Whampoa. When Manap returned home from work, Nasir wielded the knife to attack Manap and stabbed him several times on the neck. Manap, who met Nasir before and knew him, reportedly spoke in Malay, "Apa salah aku pada kau?", which was translated to mean "What wrong have I done to you?". Nasir did not reply and left the scene, but before he could take the lift at another level, he heard Manap's forlorn groans and cries in pain, and fearing that his sounds would alert the neighbours and he would not die from his wounds, Nasir returned to the outside of Manap's flat and stabbed him on the chest, thus leading to the death of 29-year-old Manap Sarlip. According to a forensic pathologist's report, Manap had been stabbed nine times on the neck and chest, and one of the knife wounds on Manap's chest was sufficient in the ordinary course of nature to cause death.

After Nasir killed Manap, he left the scene, and subsequently, Manap's corpse was discovered that same day and eventually, Nasir and Aniza were both arrested as suspects behind his death.

On 3 July 2007, following some police investigations, both Aniza and Nasir were arrested and charged with abetment of murder and murder respectively. However, Nasir was 16 years and ten months old at the time of the murder, and hence if found guilty, he would not face the death penalty but be imprisoned indefinitely at the President's Pleasure (TPP) instead, because minors who were aged below 18 cannot be executed. As for 24-year-old Aniza herself, she would be sentenced to hang if she was found guilty of abetting Manap's murder. Aniza's son reportedly did not wish to see his father's body. Subsequently, in March 2008, both Aniza and Nasir were ordered to stand trial on a later date.