The man found dead in his flat in Wembley has been named locally as Dilip Munadkat.
Neighbour Jenny Halpert said the 44-year-old worked as an outfitter in Oxford Street and lived alone.
She told the Wembley Observer: "I can't believe it. He was such a lovely man. He was hardly ever here though because he worked all the time. i'd see him at Wembley Market on a Sunday and Tuesday or Wedenesday for his day off.
"He had a male friend, a doctor, who used to stay with him."
The treasurer of the Alexandra Court Residents' Association added: "There are a lot of problems with drugs on this estate but we have never had a stabbing."
She also said the man, who is still in the flat while officers investigate, has a sister living in Milton Keynes.
Police were alerted in the early hours of yesterday morning and the first-floor flat in the shadow of Wembley Stadium has been cordoned off ever since.
Officers say the death is currently unexplained but that he died of stab wounds.