Angel Mou Pui Peng (毛佩萍[1] or 莫佩萍,[2] moe pie-PING; 9 July 1969 – 6 January 1995) was a 25-year-old female Macau national executed in Singapore for drug trafficking.

After purportedly being recruited to work as a courier for a Hong Kong-based drug trafficking organization, Mou was arrested while in possession of over 5 kilograms of high-quality heroin during a stopover in Singapore's Changi Airport.

Customs officer Brahim also recognised Mou's bag as a similar type to what Poon Yuen Chung was carrying when she was caught the month before attempting to smuggle narcotics through the same airport.

[3] Back in Hong Kong, Mou's mother heard a news report on the radio that a woman of her daughter's age, and with the same surname, had been arrested for drug trafficking in Singapore.

[17][3] Mou testified in her defence that she was a part time prostitute who was being paid US$1,000 per day for a long weekend in Bangkok,[18] after which she was instructed by her pimp, a man named "Ah Hung", to visit Singapore to service a client.

[14] Defence lawyers also stated that the man known as Ah Hung had since been arrested by police in Hong Kong for narcotic offences and that his case was pending trial, a fact they asserted backed up Mou's testimony.

In response to furter questioning about a handwritten note found in her possession which included the English words "SQ 46", "SQ28", "SWISS ZURICH", "CENTRAIR", "EUROPEAN TRAIN", "AMSTERDAM", Mou testified that a man named "Hor Fei" had telephoned the Bangkok hotel room while Ah Hung was away.

[3] On 11 March 1993, Mou was found guilty as charged and sentenced to death for importing 4 kilograms of pure heroin into Singapore, contrary to Section 7 of the Misuse of Drugs Act.

Regarding Mou's claim to have never heard the contents of the initial statement before, the judge asserted that she would have been served a copy of it in remand prison during pre-trial disclosure of evidence, and it was unbelievable she would not have studied it in detail with her defence lawyers well before the beginning of her trial.

[3] The obvious inconsistency of Mou claiming on one hand to be a streetwise high class call girl, yet being so naive and gullible as to be tricked into carrying drugs on behalf of someone else, was also cited as a reason to disbelieve her testimony.

Her explanation that the handwritten note with details about connecting flights to Europe, which implied onward travel from Singapore, was in fact ment for Ah Hung was likewise dismissed as untrue.

[3] In summary, the court did not believe Mou's version of events regarding visiting Singapore to work as a prostitute, and it was clear to the judge that she was in fact a drug courier who knowingly attempted to smuggle heroin via Changi Airport.

[24][25][26] Her lawyer Peter Yap argued that since Mou had walked towards the airport customs officers and opened her bag for an inspection voluntarily, her actions demonstrated she did not have any prior knowledge of any hidden narcotics, which backed up her claim that she was tricked into smuggling heroin.

Although Deputy Judge Wong queried the consequences of Ah Hung's actions and highlighted the fact that Mou was facing the death penalty in Singapore as a result, defence lawyer Gary Plowman Q.C.

[29] At the time of his arrest, Ah Hung was carrying a passport issued by Malaysia bearing the name of 'Sia Khim Meng' and claimed to be a furniture factory owner residing in Thailand.

[37][38][39] Upon learning Mou's family had difficulty raising money for the journey to Singapore, the manager of Hinrichs Travel Services offered two return tickets free of charge, while The Indian Resources Group donated HK$10,000 towards the total cost.

[42] Mou was visited on death row by her lawyer Peter Yap the day before she was brought to the gallows, who described her as being calm, emotionally stable and spiritually prepared for her impending execution.

[43][44] Shortly before dawn on the morning of 6 January 1995, after a two-week stay of execution and rescheduling of her death sentence, 25-year-old Angel Mou Pui Peng was hanged at Changi Prison.

[33][56] Many appeals were previously made by politicians worldwide for the commutation of Mou's death sentence, including a landmark intervention by the President of Portugal Mario Soares,[57][58][59][4][5][30][60] along with similar diplomatic efforts from the Portuguese Minister of Foreign Affairs José Manuel Barroso[47] and the Governor of Hong Kong Chris Patten.

[61][62][63] In an effort to gain clemency, Portugal's ambassador to Singapore, Sebastiao De Castello Branco, had previously described Mou as being "so poorly educated that she could not grasp the seriousness of the crime of drug smuggling".