An Indonesian maid who is a suspect in the double murder of an elderly couple in their Bedok flat on Wednesday is believed to have fled to an Indonesian island.

The Straits Times understands that she boarded a ferry from the Harbourfront Centre that Wednesday afternoon.

Chinese evening daily Lianhe Wanbao, which named her as 41-year-old Khasanah, said she had bought a ticket to either Batam or Tanjung Balai on Great Karimun.

The maid had been living with 79-year-old Chia Ngim Fong and his 78-year-old wife Chin Sek Fah in the five-room executive flat in Block 717, Bedok Reservoir Road, for about a month.

Their bodies were found in the second-floor flat on Wednesday.

It is understood that Mr Chia was discovered in the master bedroom with blood stains on his body, while his wife had injuries to her neck. Her body was found in a bathroom. Both were said to have been tied up with raffia.

A family member, believed to be the couple's grandson, had called the police.

Police investigators, who were at the scene for more than 12 hours, were seen retrieving three knives from a rubbish chute at the foot of the block late on Wednesday night.

Family members waiting in the stairwell next to the unit wept loudly when the bodies were carried past them and taken away at about 11pm.

It is understood that police have contacted their Indonesian counterparts to assist in investigations.

The maid is believed to be from Sun Employment Agency, which is owned by the couple's son, who also lives in the flat.

Online records show that the couple's daughter also works at the agency, which has been around for about 12 years and moved to its current location at Bukit Timah Shopping Centre about two years ago.

The agency was closed when ST visited yesterday, which neighbouring agencies said was unusual.

"They are usually open every day, and their business is good," said Ms Liew Peh Ling, 28, who works at Sin Yuan Resources two units away.

Another agency manager, who declined to be named, said it was not surprising for agency owners to hire their own maids in their homes.

Several neighbours described the couple as friendly and loving, and said the husband had mobility problems and required the use of a walking stick after a recent stroke.

According to Accounting and Corporate Regulatory Authority records, the couple owned 747 Departmental Store from 1977 to 1990.

They later ran three shops selling shoes, beauty products and other items till 2000.

In the flat yesterday afternoon were a handful of family members, who declined to speak to the media.

Preparations for a wake were being made in the void deck, although it is understood that the family was unable to claim the bodies from the mortuary yesterday.

The owner of a minimart at Block 718 said the news of the double murders was a shock to many residents.

"This area has always been very peaceful," said the 70-year-old proprietor. She said Madam Chin regularly made trips to the store to buy items such as eggs and biscuits.

"She was friendly and also kind-hearted. I heard that she would sometimes give the cleaner who works in the estate some money for lunch," she added.

Police investigations are ongoing.

•Additional reporting by Prisca Ang and Sean Lim