On Monday night, just 20 minutes before closing time, chaos erupted at the Ludu International Shopping Plaza in southwestern Shanghai’s Songjiang district.
Police say that a 37-year old man surnamed Lin, went on a stabbing spree lunging at strangers as he traversed the maze-like shopping centre, past food outlets and upstairs to a Wallmart.
He managed to strike 18 people and killed three of them.
A 28-year-old construction worker identified only as Zheng had just finished eating barbeque with a friend when he saw people “running, hiding and screaming”.
He tells us that he and his friend saw the man with his knives and tried to stop him – running at him and throwing chairs to try to slow him down or knock the weapons out of his hands.
But Zheng says the man was moving too quickly, and they lost him as he moved to up to the second floor.
“As everything became chaotic, we could only work out where he had gone to by hearing people’s screams,” Zheng says, adding, “As the attacker was stabbing people, he was shouting expletives in Chinese.”
Zheng says he thought the killer’s route “was defintely pre-planned”.
“I believe he deliberately chose the exits; he must have scouted the area beforehand.”
Two young stallholders on the outside the building – who saw police bring Lin to the ground – say he strode out of the shopping centre carrying a knife in each hand. Rather than running away from the scene of the carnage he had caused, he appeared calm, as if he knew exactly what he was doing.
They tell the BBC that he carried himself as if he was in control of the situation, even as police officers caught him.
Footage shared on social media captured the moment he was then taken away, his jacket splashed with what appeared to be the blood of his victims.
Police say he had come to Shanghai with the aim of “venting his anger… due to a personal economic dispute” and that their investigations are continuing.
But barely a day later, when the BBC visited the Ludu International Shopping Plaza, it was as if this carnage never happened.
There was no extended crime scene lockdown. Just over 12 hours after the deadly attack, the blood had been mopped up, and the plaza was open for business as usual.
Yet the shock remains.
A young shopkeeper, who had been rostered off at the time of the attack, says she is now scared to come to work. “It’s like a movie. You can’t believe there’d be something so terrifying right next to you”.
She points to the extra security and police now stationed near her clothes shop.
“Look at them,” she says, while admitting that she does feel safer having these officers around.
We ask about her colleagues who were at work and had to run with others who were screaming through the corridors, in order to stay alive.
“Of course they were terrified. None of them came to work today. They say they don’t dare to return,” she says.
One young woman who operates a stall selling phone accessories and other small electrical goods says that if she had delayed shutting shop by just ten minutes, she would have been in the attackers path.
“When I heard about it later, I was so scared I couldn’t sleep. Today I arrived at work obviously still scared.”
She says she feels very lucky but terrified by how close she came to such extreme danger.
This incident is the latest in a spate of knife attacks to hit China this year.
There has been discussion about economic pressures causing rifts in society, not to excuse horrendous acts like this but in an attempt to explain the seemingly inexplicable.
Then there is the question of mental illness here and how it is treated. For many years, knife attacks on strangers have come in waves in this country and they seem to be horrific copycat attempts at gaining attention.
Either way, there is something very troubling in China leading to these bloody assaults.
This week is supposed to be a time to celebrate what China has become, 75 years after the Communist Party came to power, but a killing spree ushered in the 7-day break.
Shocking footage of those who were injured, struggling in pain on the floor, spread on social media.
A woman nursing a stabbed toddler in her lap could be seen sobbing as she tried to telephone for help. Her other hand shook uncontrollably.
At the time of writing, a family member who declined to be identified, told the BBC that the two and a half year old girl was still in intensive care.
The sharing of these images and discussion of the attack is now being censored on China’s tightly controlled social media platforms although some are finding ways to talk about the subject using certain expressions to avoid being blocked.
Yet in online discussion forums, there are still those who’ve welcomed the fact that in this country – as opposed to say the United States – it is very difficult for ordinary people to get hold of guns, as access to automatic weapons would mean many more deaths in cases like this.
Yet the official move to try to erase this incident, and others like it, from the public discourse reveals the extent to which this is troubling for the government.
Managers from Walmart and the entire Ludu Plaza stopped many staff from speaking to us, sometimes even interrupting us mid interview.
Zheng for his part, says that on returning to the shopping centre the next day, he could not believe everything was simply “cleaned up” – no flowers. Nothing to mark the attack.
“I can only feel sorrow for the victims,” he said.