Detectives investigating the death of 36-year-old Zbigniew Michniewicz are appealing for further witnesses to come forward.
Officers had previously been keen to hear from anyone who may have witnessed a fight between three white males in Greenford Road.
It is now believed this assault took place inside a house in this road, on or around November 14.
DCI Noel McHugh of the Homicide & Major Crime Command said: "The house was being used as a squat, and I am particularly keen to hear from anyone who went into the house from November 10 to December 5, whether to sleep there or as a visitor.
"There has been a positive response to the police investigation from the public and in particular from the Polish community, and we encourage people to continue to come forward with any information they have."