Two local men, who didn’t want to be named, said they saw the suspect armed with two blood-stained knives outside a shop shortly after the incident began.
“I got out of my car and the guy came up to me with his hands behind his back. He said, can I speak to you,” one man told the BBC.
“He had the two knives behind his back, covered in blood.”
The man said an onlooker handed him a spirit level which he then used to confront the suspect.
“He handed me the spirit level and we just started going for it,” the man said.
“He started going towards the school so I was just trying to chase him back. He’s coming towards me the whole time.”
“The police were there but they said they weren’t allowed to get out of their car because it was a firearms incident.
“He walked away up to the flats.”
Firearms officers are routinely deployed to knife incidents and were seen going into the block of flats.
Paramedics wearing helmets and body armour were also in attendance.