Mr Sardol Singh, who lives on the 11th storey of an HDB block on Race Course Road, had a front-seat view of the rage.
The 56-year-old insurance advisor, who went to his window when he heard a commotion, said: "A big crowd gathered around a bus, knocking on it, pushing against it and tilting it."
Just as the crowd grew and became aggressive, a fire engine and an ambulance arrived at the scene. The father of two also saw policemen making their way towards the mob.
"The crowd was rowdy," he said, adding that he then saw paramedics extract the body and leave in the ambulance.
The mob started attacking the bus, three police cars and two other ambulances with poles, dustbins and rocks.
"Police officers tried to force the rioters back, but instead fell back and huddled near the fire engine," he said.
That was when the rioters flipped two police cars onto their sides.
"Suddenly the policemen disappeared into the fire engine, which left with one of the ambulances," he said.
He saw the ambulance turn into Tekka Lane and before speeding off. Meanwhile, the fire engine reversed, and hit a police car as it tried to escape the mob.
"The carnage continued," he said.
"There could have been 400 of them, operating in groups of 20 to 30. Most of the crowd stood at the sides and watched." Mr Singh saw a police motorbike overturned and set on fire by the rioters, who lit up its fuel tank.
"They were cheering as they did it. A man even ran over to the burning motorbike and danced around it," he said. Meanwhile, a vehicle was also seen burning on Hampshire Road.
Mr Singh then saw rioters turning their attention to the third police car and the remaining ambulance.