She was doing her regular grocery shopping on Thursday morning when she witnessed something shocking.
While pushing her market trolley along a stretch of shops at Serangoon Avenue 3, Madam Jariah Muhammad saw a man run up to a woman on a bench who was cradling her baby in her arms and slap the infant.
"The baby cried very loudly after that and his face looked red and swollen," said Madam Jariah, 65, a housewife.
"The mother looked to be still in shock and was very worried."
She said the man then sprinted off. The baby looked about three months old.
The incident happened at about 8.30am near Serangoon Market, at a playground facing a McDonald's outlet.
Madam Jariah told The New Paper that the man had got off a private bus parked opposite the market before running towards the mother and child, who were in the shade on a bench at the playground.
Several passers-by chased the man after he ran off, she added.
Madam Jariah said she saw the man dash across the road and go back into the bus. But passers-by stood round the vehicle to stop it from leaving until the police arrived.
Madam Jariah saw the mother rush her crying baby to a nearby clinic as soon as the culprit ran away.