A Chinese national stabbed himself on the ninth-floor ledge of a HDB block in Tampines, leaving the area heavily stained with blood, after allegedly killing a woman in the bedroom of a flat in another block 30m away.
The 37-year-old was heard negotiating loudly with police officers and threatening to jump.
After climbing back to safety, he was arrested while bleeding profusely and taken to Changi General Hospital sometime after 3am yesterday morning.
Police said that they received a call for assistance at 11.43pm on Tuesday. When they arrived at the seventh-floor flat in Block 503, Tampines Central 1, they found a woman, who is believed to be from China as well, lying motionless in a bedroom.
Paramedics pronounced the woman, who is believed to be in her 20s and in a relationship with the suspect, dead at 12.10am.
By then, the alleged killer had run to Block 505, carrying a knife. Singapore Civil Defence Force officers set up an airbag at the foot of the block.
Madam Lim Ai Lee, who lives on the eighth floor of Block 505, said that she heard "very tense" shouting in heavily-accented Mandarin, although she could not make out the words.
From her bedroom window, the 41-year-old teacher saw "red, wet splotches" on the ledge outside the staircase landing, but thought they were paint from construction work.
"There was so much. Who would have thought it was blood?" she told The Straits Times.
The five-room flat where the alleged murder happened was rented to a group of at least eight Chinese nationals. The suspect had moved in on Tuesday night itself, and the victim arrived soon after at around 9pm.
The tenants said they had never seen the new additions before. At about 10.45pm, the suspect and the woman began fighting in their room.
The other occupants heard shouting from behind the locked door, The Straits Times was told, although next-door neighbours said they heard nothing.
The noise inside the room lasted for about 10 minutes, followed by silence.
The suspect was then seen emerging from the room with a bloodied knife, partially wrapped in paper. He locked the room door behind him and ran to the neighbouring block.
The other occupants called the flat's master tenant, who was out at work at the time.
When he got back, he unlocked the bedroom door to find the woman lying face down, fully clothed, on a mattress. The walls were stained with blood.
"I shouted, 'Hello? Hello?' but she was not responsive, and so I called the police," the master tenant said. He declined to give his name or occupation.
Speaking to reporters, he said the suspect had contacted him at the weekend with an urgent request for accommodation.
The suspect mentioned that his wife would be accompanying him on some nights, added the master tenant, who had lived in the flat for the past year and had been helping the flat owners manage the sub-leasing.
A neighbour, Mr Neo Kim Tian, said that some of the tenants are believed to be factory workers as they went to work wearing uniforms.
"The unit has always been quiet," added the 54-year-old maintenance worker, who did not hear anything from the neighbouring unit on Tuesday night when the murder allegedly took place.
Police, who last night revealed that the suspect was still alive, have classified the case as murder, and said investigations are ongoing.