The 15-year-old victim of a fatal stabbing has been described as “a nice guy”.

The teenager has been named locally as Koy Bentley, who died at Rainbow House, in Water Lane, Watford, on Monday afternoon.

An air ambulance landed on Watford's ring road so the boy could be treated. Sadly, he died at the scene.

Hertfordshire Constabulary refused to confirm the identity of the victim but have advised that the next-of-kin have been informed.

Koy was a former pupil at Queens School in Bushey.

Jasmine Restrepo, 16, said: “I did not know him very well, I’d only chilled with him a couple of times, but he was funny, he was a nice guy.”

On Facebook many comments have been made expressing condolence.

Angela Bodell wrote: “What a tragic waste of a young life.”

Tammy Baker wrote: “Poor soul. Rest in peace. Let's hope they catch the scum who committed such a heinous crime.”

Amanda Lawrence wrote: “This is happening so much and on our own doorsteps scary really rip to the boy my heart goes out to his family and friends x.”

Police were treating the area on the fifth floor of the block as a crime scene.

Residents of the flats in Rainbow House were concerned and did not want to give their names. Some said they had been advised by authorities not to speak to the press.

A second floor resident said: “No one knows anything about what happened, different reports are saying different things.

“I came home at 4pm and I was escorted to my door by police and it was a one in one out policy.

One neighbour said: “I was not aware of what happened.

“I could not get into my home yesterday, I’ve only just come back. Now I am scared to go out or open my door as I have children of my own.”

Another said: “I was at home but did not hear anything until the police were here.

“I’m not sure if he lived here or not, there are so many people coming in and out of the flats here.”

One eyewitness added: “I was walking past yesterday. Armed police were in Watford intu centre, but there were only PCSOs here, no dogs or anything that you would expect if it was terrorism.

“There were police on every level of the building and they weren’t letting people in or out so it seems that there was they wanted something inside.”