Police were called to a stabbing in Midhurst Gardens, Uxbridge, around 5pm on Monday, with London Ambulance Service crews and a trauma team from London’s Air Ambulance also attending.
A 49-year-old man was treated for stab wounds at the scene but died of his injuries, the Metropolitan Police said in a statement.
Another man, aged 45, suffered life-changing injuries and is currently being treated in hospital.
A 14-year-old boy was also hurt in the stabbing, but police said his injuries were neither life-threatening nor life-changing.
The attack is not being treated as terrorism, and detectives are working to establish any relationship between the suspect and the three victims, police said.
“We treated three people at the scene in total. We took one patient to a major trauma centre but sadly, despite the best efforts of our crews, a patient was pronounced dead at the scene,” a spokesperson for the London Ambulance Service said.
“We assessed a third person before discharging them at the scene.”
A 22-year-old Afghan national was arrested at the scene on suspicion of murder and attempted murder, according to police.
Officers used a taser as they arrested the man.
A forensic tent was seen in the road on Monday night, and on Tuesday afternoon, officers in blue suits were seen scanning the scene for evidence.
Police: ‘Shocking and senseless act’
Chief Superintendent Jill Horsfall has appealed for people with information to come forward. In a statement, he added: “This was a shocking and senseless act of violence that has left one man dead and two others injured.
“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.”
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Footage posted online appears to show the suspect walking along a residential street, before two police officers sprint after him, one pointing a Taser and shouting “drop the knife” and “get on the floor”.
Several others join them before the Taser is fired and the man falls to the ground.
The force said enquiries remain ongoing and asked anyone with information to either call 101, quoting crime reference 5129/27OCT, or Crimestoppers on 0800 555 111 to remain anonymous.
