A dog walker has died and another man has been seriously injured in a triple stabbing in west London.

An Afghan national, 22, was Tasered and arrested on suspicion of murder and attempted murder at Midhurst Gardens, Uxbridge, at 17:00 GMT on Monday.

Paramedics treated a 49-year-old man who died at the scene, while the second man, 45, was taken to hospital with life-changing injuries. A 14-year-old boy was also taken to hospital with stab wounds but his injuries were not life-threatening or changing, police said.

The Home Office confirmed the arrested man entered the UK in a lorry in November 2020, was granted asylum and leave to remain in 2022, and does not live in Home Office accommodation.

He was taken to hospital as a precaution but has since been taken into police custody, the Met said.

The attack is not being treated as terrorism, and detectives are working to establish any relationship between the suspect and the three victims, the Metropolitan Police said.

On Tuesday evening, about 100 people held a minute’s silence by the cordon surrounding the scene.

They applauded at the end and the group started to disperse shortly after.

A large group of men, women and children laid flowers at the junction between Midhurst Gardens and Leybourne Road, and some lit candles.

Footage posted online appeared to show the suspect walking along a residential street, before two police officers sprinted after him, one pointed a Taser and shouted “drop the knife” and “get on the floor”.

Several others joined them before the Taser was fired and the man fell to the ground.

Ch Supt Jill Horsfall said: “This was a shocking and senseless act of violence that has left one man dead and two others injured.

“Our thoughts are with the victim’s family and friends at this unimaginably difficult time.”

She added: “The incident will have understandably caused concern to the local community.

“I have deployed multiple officers to the local area, they will be here throughout the week to provide reassurance while detectives work intensely to piece together the circumstances.

“I understand that there has been a lot of speculation online following on from this incident. We ask that you rely on us for information, and that you do not share sensitive footage.”

The family of the deceased man have been told and are being supported by specially-trained officers, the Met said.

On Tuesday, a neighbour in Uxbridge said the man who died was a bin man, and described him as “the last person on Earth that you would think somebody would go for”.

“He’s a bin man. I’ve been here two years and would see him walk past the window,” she said.

She added that on Monday he was “just doing the normal dog walk he does every day.

“I still can’t get over it. If he was five or 10 minutes later taking the dog out would the same thing have happened?”

She said she took some flowers and a box of shortbread over for his wife.

Four bunches of flowers were left near the police cordon, one of which was placed by a female neighbour from a nearby road who did not wish to be named.

She said: “Last night the police came down my road… I thought to myself ‘oh my God I wonder what’s happened’.

She said she found out what happened early on Tuesday which made her feel “absolutely sick”.

She added: “The area used to be lovely, over the years it’s really gone downhill.

“I just thought I’d come down and put some flowers down for the family.”

Another woman, who did not want to share her name, told BBC News: “The man that was stabbing random people chased after two of my son’s friends but they managed to escape.

“It’s horrendous and just on our doorstep. It’s frightening – my daughter couldn’t sleep last night because she thought the man was going to come and attack her.”

Robin Stevens, 50, who lives on the other side of Midhurst Gardens, said he heard a lot of sirens on Monday evening and he found out what happened on Tuesday morning.

He said he was “shocked”, adding: “I grew up on this street, I’ve lived on this street for 50 years and I’ve always known it to be quite a family orientated area.”

Wisam Salah, 18, who lives near the cordon, said “everyone is really panicked” after the incident.

A Home Office spokesperson offered sympathies to those impacted by the “horrific incident” and are being updated by the Met as the investigation continues.

“The priority must now be for the police to investigate so those responsible can be brought to justice,” they added.

Anyone who saw or has information about the incident are asked to contact police.