In a cul-de-sac off Upper Thomson Road, in the shambles of a derelict single-storey terraced house, the skeletal remains of two women lay undiscovered for years.
In 2006, National Environment Agency (NEA) officers entered 17, Jalan Batai for a mosquito check and found a skeleton in the toilet. Last September, a worker clearing rubble from the guest room found a skull and thigh bone.
On May 11, State Coroner Marvin Bay entered an open verdict on the latter set of remains, echoing the decision reached in the earlier case.
While neither set could be identified as DNA could not be obtained from the bone samples, the coroner's report stated that both belonged to elderly women, with the latest estimated to be from someone who died aged 60 to 70. Foul play was ruled out in both cases.
Circumstantial evidence pointed to the fact that the only residents of the house were reclusive sisters Pearl Tan and Ruby Tan, who would have been 81 and 68 in 2006.
Neither woman has been seen in over a decade, neighbours told The Sunday Times earlier this month.
A next-door neighbour, who gave her name as Madam Soon, was among those who reported possible mosquito breeding at the Tan house to the NEA, leading to the grisly discovery in 2006.
"I moved in shortly before and never met them," she said, adding that living next to the deserted house has not bothered her.
Madam Soumini Raman, who is in her 70s and has lived in the street for over 50 years, said she never spoke to them other than to say hello.
"They lived there with their mother, who was bedridden and died a long time ago," she said.
A neighbour three doors down described the sisters as friendly but not chatty. "They would smile and wave when they walked by on the way to the shops. I remember they spoke very well," said the civil servant who declined to be named.
When The Sunday Times visited the house recently, no furniture or belongings could be seen.
After complaints about mosquito breeding, unsanitary premises and overgrown greenery last year, the authorities worked together to resolve the issues, the Municipal Services Office said in response to queries.
Last August, the Building and Construction Authority (BCA) served a Dangerous Building Order and Closure Order on the owner as the damaged roof was assessed to pose a potential danger to public safety.
Unable to contact the owner, the BCA deployed its contractor to erect a temporary roof deck and clear debris, which led to the discovery of the second set of remains.
According to Inland Revenue Authority of Singapore records, the house is owned by Ms Pearl Tan.
She was a civil servant who worked in the administrative section of the National Library.
Younger sister Ruby had suffered from schizophrenia and had an outpatient treatment history with the Institute of Mental Health from 1991. Her last known review was in 2002, but it appears that her battle with the illness began much earlier.
Lawyer Freddy Neo, 63, lived next door to the Tans from 1958 to 1979. Ruby was the friendlier one, he recalled, though her schizophrenia became more severe over the years. "She would smile and talk to herself. Once, while standing outside the house, she told my mother that she wanted to beat her."
Eventually, Pearl told Ruby to stop mixing with the neighbours, he said. The sisters were Peranakan, and often spoke to each other in Malay. Their mother, a widow, died on National Day in 1970 and a funeral was held at their house.
Mr Neo recalled that both sisters loved cats and Ruby fed strays hawker food like char kway teow.
Their house was shrouded in darkness, as the blinds were always drawn. Pearl would play the piano at odd hours, the same tune every night - Beethoven's Fur Elise.
"It was kind of spooky," he said.
Retired school principal Eunice Tan, 88, said she is a cousin of the sisters on the paternal side.
The family once lived in a large house in Mountbatten. "Their father, my mother's brother, was better off than us, but I don't know what he did. Then the Japanese came and it was quite a bad period."
Madam Tan was not close to the sisters. However, she saw more of Pearl when, in her 60s, she started taking weekly piano lessons from Madam Tan's brother-in-law.
"Then suddenly, she stopped coming. Didn't say why. And later on I read about the house. It was strange and sad," she said.
The mystery of what happened to the sisters remains. Pearl was last seen at a relative's wedding in 1991. She had $227,000 in bank deposits and last drew from the account in 2004. Records show that she left Singapore via Woodlands Checkpoint on July 18 that year and there is no record of her returning.
A question mark also remains over what will become of the house.
The High Court issued an order last June that both sisters be presumed dead, and according to court documents, a niece, Madam Woon Sook Han, applied to the Public Trustee's Office to administer the estate of the Tan sisters in 2013.
However, Mr Kesavan Nair, director of Genesis Law Corporation, which is acting for a claimant to the estate, told The Sunday Times that no one has stepped forward to administer it. Mr Nair, who declined to reveal his client's identity, said that as far as he is aware, neither sister left a will.
While the mystery of the sisters' deaths may never be solved, one thing is clear: they led such an isolated existence that when they died, the world failed to notice.
"I suppose when you live on your own and don't mix with people, that's what becomes of you," said Madam Tan. "It's very sad, we could have done something if we had known it was so bad. But they didn't seek any companionship, they just kept to themselves."
•Additional reporting by Ang Qing