When Mr Rajoo Mani read an article in January that described the unsolved case of a girl who was found murdered in Singapore in 1995, it brought back a flood of memories.

He was nine years old when police officers found his father's body along Clementi Road on Oct 6, 1974.

Then 37, Mr Vartharajoo Krishmasamy suffered about 25 slash and stab wounds. His killer - or killers - was never found.

"I was playing with a friend, then I saw these men come out of the lift and go downstairs to where our flat was... I remember my mum crying and saying that my dad had left us but not mentioning anything about what happened," Mr Mani, 56, told The Sunday Times in a recent interview.

The men turned out to be police detectives.

Mr Mani's family was then living in a rental flat in Redhill, an area rife with gangsters, according to old reports.

There was some speculation then that Mr Vartharajoo's murder might have been the result of gang violence.

But Mr Mani said his father, a port labourer by day, had mainly spent his time working and did not even have any tattoos, a common gang symbol at the time.

When he was home, he would fix electronic items or do carpentry work to earn extra cash for the family.

"The night before (the police came), we were all at home and he said he was going to help a friend fix his radio.

"He would usually be back before midnight but he never came back," said Mr Mani, as he clutched a plastic folder containing yellowed newspaper clippings of the murder and his father's death certificate.

Mr Vartharajoo was found by the police at about 7am near what was then the Kent Ridge university complex, about 40m from his light-blue Vespa scooter, which was lying on its side. His helmet was still on him.

"I know that the police pour their hearts and souls to catch these culprits, but how come this guy (the killer) got away," said Mr Mani, an associate at a bank.

He had contacted The Sunday Times after reading about the Lim Shiow Rong case. The seven-year-old girl's body was found in a drain along Jalan Woodbridge on June 25, 1995.

Hoping for answers, her mother and sister appealed to the police to review the case. It prompted the Criminal Investigation Department to reassure them that investigations are continuing.

Mr Mani hopes that anyone with information on his father's case will come forward.

He said: "I know it's pretty hard to catch whoever killed my father because it's been over 45 years and whoever did it might not be around. But there are so many questions and things I still don't know."

His father was the sole breadwinner of the family, which included Mr Mani's mother, grandmother and three siblings.

The children were all in primary school at the time and the family was extremely poor. They stayed in rental flats and struggled to pay the bills.

His elder brother and sister finished primary school and went to work at a factory where his mother was a lift attendant.

His mother fractured her hip in 1996 and became a wheelchair user. She was later diagnosed with various ailments, including osteoporosis and rheumatoid arthritis, and died in 2012.

While she was alive, Mr Mani's mother did not bring up her husband's murder and refused to let her children put up their wedding pictures.

"All she used to say was that even if the (murderer) got away with it, everyone would face judgement some day... What he did is really inhumane," said Mr Mani.