9 Biggest Unsolved Crimes in Singapore History. Number 5 will change your view on curry forever

9 Biggest Unsolved Crimes in Singapore History


Update: We've added two more cases thanks to suggestions from our readers.

Even as a young nation with a relatively short history, Singapore has had its fair share of unsolved crimes. The real life whodunits which were never solved. Be it bone-chilling murders or vanishing acts, there's just something about these unsolved crime cases which hits home hard.

Nobody knows the exact truth behind these stories. All we know is that these mysteries have been unsolved, and will continue to be in the near future. Maybe with this post more awareness would be made for some of these stories. Who knows, some internet super sleuth might even provide new insights to some of these cases.

But until then, nobody knows what happened.

Time marches forward callously, relentlessly, without any signs of stopping. Life will go on, and the mysteries will remain obscure and unsolved forever.


1. McDonald's Boys Case (1986)



This is probably Singapore's most mind-boggling mystery to date. The case involved two ordinary primary school boys, Toh Hong Huat and Keh Chin Ann, who were good friends with each other. They were last seen together near school at 12.30pm, but simply vanished without a single trace after that. Their books and bags were found under a tree, but not a single person knew where the boys went to.

This case was dubbed by the press as the McDonald's Boys, because the people from McDonald's were moved by the story of the boys' disappearance, and offered $100, 000 as a reward for information. 

However, despite the huge reward offered by McDonald's, huge press releases and a police search which extended to neighbouring countries including Malaysia and Indonesia, the boys were never found. 

Possible Theories:

1. Kidnapped for money

Some have speculated that the boys might have been kidnapped for money, but as far we know, both of them came from humble backgrounds, and no demand for ransom had ever been made. 

2. Accident

Perhaps the boys were playing somewhere and got into an accident, such as drowning. However, no bodies were found.

3. Kidnapped by members of an illegal syndicate

We've heard of cases where children were kidnapped and forced to turn to begging in foreign countries. This might have happened to the two missing boys. 

4. Ran away from home

Perhaps, just perhaps, the boys escaped Singapore on their own, and are currently well and alive in some other country. 


2. Queenstown Shooting Incident (1972)


b2ap3_thumbnail_queenstown.JPGSource: Good Morning Yesterday

As a country with one of the strictest gun laws in the world, this incident was considered shocking. Firstly, the shooting happened in broad daylight and secondly, the killer was never found. Yes, let me repeat that.

Someone was shot and killed in Singapore in broad daylight and the killer was never found.

A 22-year-old seamstress Cheng Li Zhen was walking along Queenstown with her sister when she suddenly screamed and collapsed to the ground with blood oozing out from her chest. It was only after she was in the hospital that they found that it was a gunshot wound. She never regained consciousness and passed away in the hospital soon after. More than 40 years have passed, and no one knows exactly what happened and why she was shot. 

Possible Theories:

1. Killed by a sniper

The police originally thought that it was a sniper's doing from a nearby building. They later confirmed that the bullet was a 0.22 calibre round and probably fired from close distance from a handgun. However, the sister and members of the public did not spot anyone suspicious. 

2. Shot by a guard nearby

If the victim was near the Police Reserve Unit or Queenstown Prison Area, she might have been accidentally and unluckily shot by one of the policemen or guards . So much for being in the wrong place at the wrong time.

3. Mistaken identity

According to the victim's family, the girl did not have enemies. It could have had been a case of mistaken identity, in which the killer got the wrong person.


3. Geylang Bahru Murder of the Tan Children (1979)


b2ap3_thumbnail_tanchildren.JPGSource: Singapore Press Holdings

This incident is considered the most brutal and inhuman murder case in Singapore's crime history. 

Four children from the Tan family, aged between 5 to 10 years old, were violently murdered in cold-blood in their own house while their parents were out at work. They were cruelly hacked and slashed to death in the bathroom. Slash wounds were found on Chin Nee’s face, while Kok Peng’s right arm was almost severed. According to the pathologist’s report, each child had a minimum of 20 slash wounds on his or her body.

The police concluded that the murders were premediated and the perpetrator or perpetrators took care to avoid leaving incriminating evidence. However, there were bloodstains in the kitchen sink and the killer or killers were believed to have cleaned themselves before leaving the flat. 

The murder remains unsolved up till today, and remains as one of the most blood-chilling murder cases which shook the whole of Singapore.

Possible Theories:

1. Killed by thieves or robbers:

Thieves and robbers were rampant then, and a group of them might have had entered the Tans' house to steal, and killed the children to silence them. However, the police confirmed that no items were reported missing from the house. 

2. Illegal tontine scheme:

The children's uncle told the press that the murders could have been related to an illegal tontine scheme, and police pursued the possibility of the killer being a discontented gambler. However, that angle of investigations did not lead to the murderer and the Tans told the media that they had not offended anyone.

3. Killed by their neighbour:

A taxi driver from Toa Payoh reported that a man in his 20s who walked with a lurch had boarded his taxi near Block 96 along Kallang Bahru Road, nearby the scene of the murder, at about 8:00 am on the morning of the murder. The taxi driver said that the man had bloodstains on the left side of his body and carried a knife which “banged against the taxi door” when he alighted at Lavender Street.

The children's father matched the taxi driver’s description to a neighbour of his, a young man who visited the family’s flat almost daily to use their phone and who was known as “Uncle” to the whole family. In a police line-up, the taxi driver picked out the neighbour as the man who had boarded his taxi. However, the neighbour was released after two weeks due to a lack of evidence connecting him with the murders. The man, who was Malaysian, later moved out of Block 58 with his sister.


4. Abduction of Social Escorts (1978)



Source: Singapore Press Holdings

On August 20th, 1978, there was an incident in which 5 women were abducted. 5 females, believed to be social escorts, were hired by a group of foreigners who claimed to be Japanese, for a floating party out at sea. The 5 ladies set off on a boat from Singapore Harbour. All of them disappeared together with the boat and never came back. 

Out of the 5 ladies who disappeared, one of them was 24 year old Singaporean Diana Ng. This case made the headlines, and over the years, rumours and updates about the missing escorts were heard but none of them led up to any conclusions.

Possible Theories:

1. Sold as sex slaves

The foreigners who hired the ladies were probably part of a crime syndicate. The most popular theory that materialised for this case is that the ladies were sold as sex slaves, possibly in some Middle East country.

2. North Korea abduction

In 2005, Mr Robert Jenkins, a Japanese who was abducted to North Korea (who later managed to get back to Japan) testified that one of the missing escorts, Yeng Yoke Fun, looked very similar to a lady he saw working for an amusement park in Pyongyang from 1980 to 1981. Hence, it's possible that the social escorts may have been captured and trapped in North Korea. 


5. Curry Murder (1987)



Source: SPH

The story started in 1985, when Ayakanno Marimuthu, a live-in caretaker of Changi chalets, was reported missing by his wife, Naragatha Vally Ramiah. She said that her husband went to Genting Highlands but never came back. 

Two years later, based on the investigations of detective V. Alagamalai, enough evidence was gathered. The police swooped in on five places and detained eight suspects.

Initially silent about the victim, one of them eventually spoke out and said that the victim had been battered to death with an iron rod in the Orchard Road Presbyterian Church’s caretaker quarters, chopped up into pieces and cooked into curry using a large aluminium pot, the same kinds used to make nasi biryani.

People suspected they might have had eaten the curry that Mr Ayakanno Marimuthu was cooked in, causing widespread panic. This case caught the attention of the international media but at the end of the day, the murder suspects were released due to insufficient evidence.

Possible Theories:

1. Killed by wife's family

According to the detective, Ayakanno was an alleged wife beater with a temper when under the effects of alcohol. Sick of the constant violent acts by Ayakanno, the wife's family might have killed him in order to save his wife from further abuse. 


6. Mona Koh Shooting (1994)



Source: HealthXchange

Back in the 90s, Mona Koh ruled the nightclub scene and was considered one of the top mamasans in Singapore. On the fateful day of the incident, Mona Koh was shot twice while she was waiting for a lift at Katong's People Complex. The first bullet hit her face and the second, her spine, making her permanently wheelchair-bound.

Mona Koh never found out the identity of the gunman.

Possible Theories:

1. Target of monetary conflict

With clients such as high-profile entrepreneurs, industry captains and whatnot, Mona Koh might have been the unfortunate target of monetary conflict.  

2. Vengeful competitor

Back then, Mona Koh was the top mamasan who ruled the local nightclub scene. She was said to be very influential, with what was said to be the biggest stable of girls under her charge. Perhaps a jealous and vengeful competitor had tried to bring her down. 

3. Gunman hired by an enemy

Being in the nightclub industry meant that Mona Koh knew a lot of people, some of them with shady backgrounds. Mona Koh might have had made some enemies, one of whom was determined to get back at her. However, Mona Koh insists that she can't think of anyone who would do such a heartless deed to get back at her.


7. Winnifred Teo Case (1985)



Source: Singapore Press Holdings

Winnifred Teo Suan Lie, then a 18-year-old Catholic Junior College student was the victim of a rape and murder case. On May 22 1985, she left her house for a jog, but never returned home. Her mother made a police report, and unfortunately, Winnifred's naked body was later found lying in undergrowth off Old Holland Road.

She suffered multiple stab wounds on her neck. Her body showed signs of a fierce but futile protest, probably made when she was trying to fight off her killer(s). An autopsy showed that she had been sexually assaulted, and died of massive bleeding from the stab wounds. The murderer(s) were never discovered.

Possible Theories:

1. Business Rivalry

The CID considered several theories, and business rivalry was one of them. They did not rule out that the murder could have been related to "jealous business rivals" of Winnifred's father, who was a managing director with Kuok Brothers and overseas at the time of the murder. Investigators said that they "might have wanted to get back at his family members while he was out on overseas business". 

2. Victim of sexual assault

Residents and joggers in the area said they frequently saw a slim man, who had exposed himself before to passing female joggers. The police arrested the man for questioning, but released him after they failed to make any connection. 

The scene of the attack was situated at a rural area between Ulu Pandan and Bukit Timah. A large number of men from nearby construction sites usually gather around the area, so it's possible that a few of them might have been the culprits. 

Sadly, even after so many years of investigation, the police has came up with nothing. The killer(s) remain at large. 


8. Bukit Batok Rape Case (2000)


Bukit Batok is the site of large parks and other nature spots, but it is also famous for being the site of a few shady and bloodcurdling crimes, the most famous being the rape and murder case which happened back in 2000.

27-year-old Linda Chua, an oil company executive, was jogging at the Bukit Batok Nature Park around 10AM when she was attacked. A passer-by heard her cries for help and called an ambulance. Linda Chua was found lying in a 10-metre ravine naked, with a bloodied nose and mouth, and her clothes next to her. Unfortunately she did not manage to survive, and passed away a week after the assault. 

Possible Theories:

1. Victim of sexual assault

Like the Winnifred Teo case, Linda Chua was most probably the victim of sexual assault. The Bukit Batok Park is known for being quiet and secluded, full of concrete paths with thick vegetation on either side, making Bukit Batok susceptible for crimes to happen easily. 

What makes the case more chilling is that the assault happened in broad daylight. We tried very hard to uncover more information regarding this case, but met with many dead ends. Even newspaper reports were scarce, which made it hard for us to find any related pictures.

This is one of the rare cases with minimal information available, which adds a thick air of mystery to the unsolved case. We could not even find a relevant picture for it. Hopefully in the future, someone will come forward with information, or police will be able to find more clues to help solve this case. 


9. Kovan Double Murders (2013)


b2ap3_thumbnail_kkovan10076e.jpgSource: Straits Times

Our last story is already solved, so there is no question who the killer was. The mystery here is what could have motivated this killer to commit such a gruesome act. And this happened in Singapore just last year!

The shocking Kovan double murder of a father and son was made worse by the fact that the son's body was dragged by the culprit's car in broad daylight - in front of many shocked members of the public. 

Following the trail of blood left by the son, Tan Chee Heong, the police ended up at a house at 14J Hillside Drive, where they found the body of his father, Tan Boon Sin. A nationwide manhunt was launched for a male suspect who had fled the scene. Three days later, former Singapore Police Force senior staff sergeant, Iskandar bin Rahmat, was picked up with the help of Malaysian police, at Danga Bay in Johor and identified as the killer.

As this case happened just recently, there is still a chance that the motive behind this shocking mystery will be unveiled in the future. But what remains appalling is the fact that this atrocious act was committed by a policeman, who knew the victims personally.

Possible Theories:

1. Personal feud 

Since the murderer knew the victims personally, it's possible that both parties could have had some disagreement going on between them. A personal feud might have been the reason for the murders, with Iskander killing them in a fit of anger.  

2. For money

Iskander was revealed to be struggling with personal debt issues. He was declared bankrupt a day after the murders, owing a bank approximately S$62,000. He might have killed the Tans for their money, in a desperate attempt to clear his debts. 


Will the Mysteries Ever Be Solved?


Many of these mysteries have boggled the minds of Singaporeans for decades, with no end in sight. Some of them are intriguing, yet others are downright bone-chilling. One can only hope that these mysteries will be solved in the future, where light will be shed on the years of investigations and speculations. Most importantly, it will also bring closure to the victims and their families.

Think you know any other possible theories, or any other unsolved crime cases? Feel free to join in the discussion and share your views with us. It was thanks to your suggestions in our recent 16 most horrifying incidents in Singapore article that helped us come up with this list.

As cliché as it sounds, this is a reminder that low crime does not mean no crime. Think again before you become complacent and decide not to lock your door, leave your spare key under that obvious choice of a flower pot or start jogging alone at night along that dark secluded path.

This is a strong reminder to us to look out for our loved ones. Stay safe, Singapore.


Latest Uniquely Singapore reviews


I can read minds. You will also like:

Singapore Slang 2
20 MORE Singaporen Slang Only A True Blue Singaporean Will Know

15 Homes so Beautiful you won't believe they're HDB flats
15 Homes so beautiful you won't believe they're HDB flats

Cafes in Singapore
15 Delightful Singapore Cafes with No GST & No Service Charge 

Road Trip Singapore
14 Ulu Places you can take a road trip to in Singapore 

Fashionistas to follow
15 Singaporean Fashionistas to Follow on Instagram right now

Best Halal Restaurants
The 20 Best Halal Restaurants you can find in Singapore 


Also watch us on TheSmartLocalTV!

Shakespeare in the Park, Merchant of Venice Review
Beer Market - Chicken Rice Pizza and the only Beer...