On Friday morning, Mr Ken Ong Wei Poh, 37, was believed to have attacked his wife, Madam Koh Siang Hua, 39, with a knife in their third-storey apartment in Park View Mansions on Yuan Ching Road.

He is believed to have turned the knife on himself after that.

The attack happened while their five-year-old son was at kindergarten.

Mr Ong also attacked their Filipino maid, Ms Jamelarin Jasmen Corpuz, when she tried to intervene during the attack.

Covered in blood and with several gaping wounds, Ms Jamelarin fled the apartment and ran into a cleaner who helped call the police.

When emergency responders arrived, they had to break into the apartment, where they found Mr Ong and Madam Koh in a bedroom.

Both were taken to the National University Hospital, where they were pronounced dead.

At 8.09am that day, Mr Ong had posted a 2,050-word note on Facebook titled "Final Note". The same note was also sent to Singapore media, including The New Paper, at 8.11am.

Police said they received a call for assistance at 7.56am.

In the note, Mr Ong described his failed marriage and accused his in-laws of treating him badly.

He also said his wife had shown him little respect and would not let him work in her family's furniture business, TYT Corporation.

The couple were going through a divorce. In documents seen by The Straits Times, Madam Koh accused Mr Ong of being a narcissist and a chauvinist who wasted money and refused to work, spending his time in front of computers and the television instead.

In his reply, which Mr Ong wrote himself because he could not afford a lawyer, he said Madam Koh acted like a boss instead of a wife, was selfish, stayed out late with a girlfriend, failed to give him enough allowance, and that her family refused to hire him at their company.