The retiree was sitting at his usual spot in the void deck when he heard a loud bang.
Thinking it was high-rise litter, Mr Poh Bock Tho, 73, went to take a look.
He was shocked to see a man and a toddler sprawled face down on a grass patch near the bottom of the block.
Just minutes earlier, he had seen the man carrying a little girl and walking to the lift landing.
"He said selamat pagi (good morning in Malay) to me before going into the lift," recalled Mr Poh, who had known the man for at least 10 years. Mr Poh said it was the first time he had seen the man carrying his child around.
The tragedy happened at a bustling neighbourhood in Yishun Street 22 at about 11am on Thursday.
Police said that they found a 40-year-old man and one-year-old girl motionless at Block 280.
The Singapore Civil Defence Force sent an ambulance and the man was pronounced dead at the scene.
The child was taken to Khoo Teck Puat Hospital where she died later.
Mr Poh believes the father and daughter had fallen at the same time because he heard only one loud thud.
He also saw that the girl, who was in a red flowery dress, was bleeding from her ears, and lying about a metre away from her father.
Mr Poh said: "Every family has problems, but it is important to look on the bright side of life.
"The child is innocent.
"Since it's your child, you should never hurt her."
He added that the man appeared to be financially well-off.
The family lives in an executive maisonette in a four-storey block next to the one from which the man and child had fallen.
They are believed to have fallen from a flowerpot rack on the 12th storey.
The man is also known among motorcyclists in the neighbourhood because he owned an impressive motorbike - a BMW 1300 GT.
Mr Poh said in Mandarin: "When I saw him, he was wearing a long-sleeved shirt, long pants and leather shoes.
"He looked just like how he was usually dressed for work."
The wife of the dead man is reportedly pregnant and due to give birth in two months.
Before his death, he had breakfast with his wife and told her that he would take their daughter shopping, Shin Min Daily News reported.
When The New Paper visited the block on Thursday evening, more than 15 relatives had gathered in the man's unit and at the void deck.
A woman, who identified herself as the man's sister-in-law, said that the extended family was in shock.
"We don't know anything and we don't want to speculate," she said, declining to be named.
A resident in the same block, who declined to be named, said that the man's wife had quit her job after giving birth to their first child.
He added that the family kept to themselves, but they would exchange greetings with the neighbours.
The police have classified the deaths as unnatural and are investigating.
This is the second incident this week involving two family members falling.
On Monday, a 66-year-old man and his son fell to their deaths at a Clementi West block.
Samaritans of Singapore (24 hours) 1800-221-4444
Singapore Association for Mental Health 1800-283-7019
Silver Ribbon 6386-1928
Institute of Mental Health's Mobile Crisis Service 6389-2222
Care Corner Counselling Centre (Mandarin) 1800-353-5800
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