Police have arrested a woman who was caught on video punching and kicking her elderly neighbour who is said to have suffered more than 50 blows during the 20-minute attack.
The woman, in her forties, is also under investigation for hurling abusive language at police officers who were called in to help.
The woman was seen approaching Madam Toh Siew Hong, 65, from the back, at the lift lobby outside their units in Chai Chee on Saturday. She hit Madam Toh who retaliated by hitting her back. She then started to attack Madam Toh, punching and kicking the housewife mostly in the face.
The shocking footage - which has since gone viral after Madam Toh's daughter-in-law posted it on her Facebook page - was recorded by the closed-circuit television installed outside the housewife's flat.
Madam Toh's daughter, who wants to be known only as Ms Yap, told The Straits Times that the woman had moved in opposite their home in January this year and has caused "trouble" in the last few months, blasting loud music at night. Neighbours had lodged several complaints against her with the police.
Ms Yap said it was unclear what triggered the attack.
But she added: "In the last few weeks, she had approached my mum several times, provoking her and using vulgar language against her, She probably thought my mum had complained about her to the police, but my mum did not."
Madam Toh, who is warded at Changi General Hospital, suffered bruises near her eyes, and required several stitches on her face and at the corner of her mouth.
The son-in-law of the attacker told Lianhe Wanbao that she is mentally unstable, and had sought treatment at the Institute of Mental Health.