John Smith, 52, was found critically injured at Misk Knowes, in Stevenston, North Ayrshire, on Saturday.
He was taken to Queen Elizabeth University Hospital in Glasgow where he died on Tuesday.
A post mortem examination will be carried out and police said they are treating his death as murder.
A 30 year-old man also found badly injured at the Misk Knowes property at around 3.15pm on Saturday was treated at Crosshouse Hospital in Kilmarnock then later released.
Officers earlier said they are investigating whether the discovery of a man’s body in the same town earlier that day could be linked to the incident.
Police were called to Glen Crescent in the town at around 10.50am on Saturday where a 56-year-old man was found dead.
A post-mortem examination will be carried out to establish the exact cause of death, but it is currently being treated as unexplained.
Detective Chief Inspector Allan Burton said: “Inquiries are continuing into the circumstances surrounding the incident within the property in Misk Knowes on Saturday afternoon, to establish who is responsible for the murder of the 52 year-old man, and the serious assault of the 30 year-old man.
“From our inquiries over the past few days we believe that a car drove off at speed from Misk Knowes around 3pm on Saturday afternoon. I would urge anyone who may have information on this vehicle and its occupants, or indeed if someone saw a car being driven erratically in the local area to contact us.”