Emergency services were called to the property on Loampit Vale on Sunday morning and the man was pronouced dead at the scene.
A 53-year-old has been arrested after attending a south London police station. An investigation into the death continues.
“I appreciate there is a lot of concern among local people following this tragic incident,” said Detective Chief Inspector Neil John.
“While our enquiries are at a very early stage, I am satisfied that there is no wider risk to the community. A man has been arrested and we are not currently looking for anyone else in connection with this incident.
“Anyone who feels they might have information that could help us get to the bottom of what has happened here should contact us immediately.”
Chief Superintendent Trevor Lawry said his thoughts are with the victim’s family.
“My officers remain on scene and will be around in the coming days to reassure the public and support our colleagues in Specialist Crime as they work to establish the chain of events that have led to a man losing his life.
“Anyone who has any concerns, or information that could help us, should approach those officers and tell them what you know; no matter how insignificant it might seem, you may have information that could be very important.”
The victim’s next of kin have been informed. Formal identification awaits.
A post-mortem examination will be held in due course.
If you have information that could help, call 101 or tweet @MetCC ref CAD 2486/14Aug. To remain anonymous contact the independent charity Crimestoppers on 0800 555 111.