Detectives are appealing for information following the death of a man in Westminster.
Police were called by the London Ambulance Service (LAS) at 19:49hrs on Thursday, 21 June to reports of a man found collapsed with a number of injuries - which included a severe head injury - in a flat on Page Street, SW1.
He was taken by LAS to a central London hospital where he died at 23:46hrs.
His next of kin have been informed. He has been named as 39-year-old Matthew Thomas.
A post-mortem examination will be held in due course. The death is currently being treated as unexplained.
Matthew was known to the occupants of the flat.
Officers from Westminster Borough are being supported by the Homicide and Major Crime Command.
Detective Chief Inspector Noel McHugh, said: "We believe that Matthew may have been working as a scaffolder, and it is possible that he sustained his injuries at work. I need, as a matter of urgency, to speak with anyone he was working with, and who may have seen him fall or injure himself. Can you help us establish where he was working?
"At this early stage, it is also possible that he was the victim of an assault. I would ask that anyone who knows Matthew; anyone who can assist with his movements over the last week, especially on Thursday, please make contact with officers. We need your help in building up a picture of his movements before he went to the flat on Page Street.
"Any piece of information may help us to find out what happened to Matthew. It is important that we establish the facts for his family."
Anyone with information is asked to contact officers on 020 8785 8099 or via 101 quoting reference 7931/21June.
Due to the unexplained nature of Matthew's injuries, a 49-year-old man and a 53-year-old woman were arrested at the scene on suspicion of murder. They were taken to a north London police station for questioning before being bailed to a dated in late June.