Heroic residents stepped in when they saw a man on roller skates stabbing a man.
Three people have been rushed to hospital following today's terrifying knife attack .
None of their injuries are believed to be life-threatening.
A police cordon remains in place on Wells Road near to Redcatch Road and one man has been arrested.
Now witness Gary Stancer has described the moment his friend was attacked.
He was in a pub with his friend Rob Day when he said he saw a man had been stabbed. They rushed out to help and, he says, his friend Rob was then attacked.
"He said to me I've been stabbed," said Gary. "A man with a red shirt, whoever the man with the red shirt is a hero.
"Rob was stabbed, he said to me 'I've been stabbed'. The man with the red shirt stepped in. I picked up a sign and hit him. I fell over.
"We chased him up the road."
A man was Tasered and arrested by police, Mr Stancer said.
A spokesperson for Avon and Somerset Constabulary said: "At 3.10pm today we began receiving reports a number of people had been assaulted in the south Bristol area.
"Officers attended and subsequently arrested a man in his 30s on Redcatch Road. He remains in custody.
"Three people have been taken to hospital with injuries which aren’t believed to be life threatening. "A full investigation is already under way.
"While we’re keeping an open mind about the motive, we can confirm we’re not treating the incident as terrorism.
"Road closures are in place as emergency services carry out enquiries and motorists are advised to avoid the area."
