A man aged 33 has been arrested on suspicion of murder following the death of a man in Action.
A murder investigation was launched after was found deceased in a multi-occupancy residential property on the morning of Sunday 27 January.
Police were called to the flat in Alfred Road, Acton, at 10.15hrs following concerns raised for his welfare.
Officers and the London Ambulance Service (LAS) attended.
The body of man, aged 34, was found at the scene. He had been fatally attacked. His immediate next of kin have been informed. Efforts are underway to trace his extended family members in Poland.
The Homicide and Major Crime Command are now investigating. They are confident they know the identity of man but formal identification awaits.
A post-mortem examination will be carried out in due course.
The arrested man remains at a north London police station for questioning.
DI Mark Richards from the Homicide and Major Crime Command said: "This man was fatally attacked in his own home. Our efforts are focused on bring the culprit(s) to justice. At this early stage there is nothing to suggest entry to the property was forced. A number of active enquiries are underway including forensic analysis at the crime scene and the gathering and review of local CCTV footage.
"We continue to appeal for help from the local community who may have seen or heard something that could be vital to our investigation. Were you out for a jog or walking around in the vicinity of Alfred Road on the day of the attack? We are ready to take your call and information in confidence."
Anyone with any information about this incident is asked to call police on 0208 358 0400 or Crimestoppers, anonymously, on 0800 555 111.
You can also also tweet information to police via @MetCC
+ Bearing down on violent crime on the streets of London continues to be a top priority for the Met. Teams across the city are working tirelessly - day and night - to identify and pursue offenders, help bring perpetrators to justice, take weapons off the street, support victims, engage and reassure the public, and keep our communities safe.
However, the police cannot solve this problem alone. The police, our partners and the public must work together to deal with knife crime and prevent further lives being lost. Communities have a vital role to play in tackling violent crime. We want to hear from anyone who may have information about people who may carry knives or firearms, or who are involved in organised drug crime and violence. This information could save lives in the future. If you aren't comfortable speaking directly to the police, please contact the independent charity Crimestoppers. They do not ask your name or trace your call.
If there are any young people who either have information about violence or knife crime, they can visit www.fearless.org where they can pass on information anonymously. Fearless is part of the Crimestoppers charity, and is also independent of the police.
If you need help or information to support someone you suspect is involved in knife crime, or you want to assistance yourself, then you can visit www.knifefree.co.uk or LondonNeedsYouAlive.