Reading's Forbury Gardens were dotted with groups of friends relaxing in the early evening sunshine when the peace was shattered by a commotion and frantic shouts of "run". Three people had been stabbed to death in an attack that has left the town reeling.
"Everyone was just having fun and then suddenly a man shouted," said Lawrence Wort, who had been sitting nearby.
The 20-year-old said he could not make out the words or in what language they were spoken.
What he could see was a man with a "massive knife".
"He stabbed the first person - they were sat in a circle in a big group of about eight to ten people - and he darted round anti-clockwise, got one, went to another, stabbed the next one, went to another and stabbed them."
Khairi Saadallah, 25, was arrested at the scene by unarmed officers who have been praised for their "incredible bravery".
He remains in police custody on suspicion of murder.
As well as those killed in the attack, three more people were injured.
Greg Wilton, who tried to help the victims, said he had been left "very shocked and shaken".
He was having a picnic with his wife and three friends, after listening to speeches at a Black Lives Matter protest held in the park earlier in the day.
"We stayed in the park as the weather was nice and had some drinks," he said.
"At one point without much noise we noticed a commotion on the other side of the park.
"We ran over and without seeing an attacker we found three men lying on the floor bleeding profusely from what we thought was their heads, necks or body.
"Another member of the public took off his t shirt and tried to stop the bleeding alongside someone we assume to be his girlfriend.
"Me and my friend, Tom, put a second victim in the recovery position and tried to stem his bleeding from his ear with my canvas shopping bag."
He said Reading as normally a "relatively peaceful" town.
On Sunday, an atmosphere of shock and mourning was palpable in the town centre - where bloodied roads were cordoned off by police.
Large areas outside the gardens are taped up, and the streets are largely deserted but for police officers, journalists and TV crews.
Locals who had ventured into the town said they were frightened.
"I was scared to be here but I have to be here for work," said Marie Castro, from Slough, who works at a coffee shop in the town.
The attack "doesn't seem right for Reading", she said.
"It's multicultural and really friendly. I was really shocked when I heard the news".
Alice Penney, who moved to Reading from Kent a year ago, said she left the town and went to a friend's house after hearing about the stabbings.
"I was absolutely mortified. I had been at the protest a few hours earlier when I heard the news. It was something I couldn't process.
"I feel like we cheated death. It's a safe place, normally. It's very confusing."
As helicopters patrol the town from above, on the ground floral tributes have been laid.
James Hill, from Reading, said: "I've come here today because I've lived in Reading all my life.
"This park is very close to my heart - I know it very well - and I feel obliged when something as bad as this happens, that I play my part and make a tribute."
One card left near the scene reads: "There are no words that anyone can say to express how horrible and senseless this was."
Another simply states: "Reading weeps."