Attacker known to be aggressive
He may be a well-known face in his Toa Payoh neighbourhood, but no one knows his name or whether he lives alone or has a family.
When shown a photograph of him in Chinese daily Lianhe Wanbao, several residents and shopkeepers knew him as someone who was notorious for his aggression towards passers-by.
A dim sum stall owner said the man would often sit at his stall but not cause any trouble - until this year.
He said: "Not sure why, but his character just changed entirely."
Madam Salamah Awi, a 59-year-old resident who recognised him from the photo, lowered her voice and said: "He's very aggressive and would scold people for no reason. He scares me."
A resident in his 70s initially said he had nothing much to say about the man. But when told that he could remain anonymous, he said the man was prone to aggression recently and few would have been surprised to learn that he had turned violent.
He added that he had previously seen the man in a fight at another food centre in the neighbourhood.
"He could be mentally unsound or pretending to be crazy, because he wasn't always this way. I doubt anyone knows what happened to him," he said in Mandarin.