The 49-year-old man, named locally as Wayne Broadhurst, was killed on Monday evening (October 27) in Uxbridge.
Two others were also injured in what police called a “senseless act of violence”.
One neighbour who did not want to be named said Mr Broadhurst was a binman who was “just doing the normal dog walk that he does every day”.
“I’ve been here two years and would see him walk past the window,” she said.
She described him as “the last person on Earth that you would think somebody would go for”.
She said she took some flowers and a box of shortbread over for his partner and added: “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?”
Police and ambulance crews were called to Midhurst Gardens in Uxbridge at around 5pm on Monday where the three victims were stabbed.
Mr Broadhurst was treated at the scene but died, while another man, aged 45, suffered life-changing injuries.
A 14-year-old boy was also stabbed, but his injuries are not life-threatening or changing.
The attack is not being treated as terrorism, and detectives are working to establish any relationship between the suspect and the three victims.
A 22-year-old man was arrested at the scene on suspicion of murder and attempted murder.
Chief Superintendent 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.
“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.
“If anyone saw or has any information about the incident, then please come forward to police. We appreciate any information that you may have.
“There will be a crime scene and a heavy police presence within the area over the next few days, I thank residents for their patience.”
Anyone with information can call police on 101 quoting the reference 5129/27OCT, or to remain anonymous contact Crimestoppers on 0800 555111 or online.
