Detectives have released CCTV footage of a man setting fire to a front door in a “seemingly motiveless attack”.
A man is believed to have poured ignitable fluid through the letterbox of a house in Dower Avenue, Wallington, and set it alight.
The attack took place at 6.25am on Thursday November 1 as the home owners were asleep in bed.
The retired couple were woken by their smoke alarm sounding and put out the blaze with a fire extinguisher.
The front door was damaged beyond repair and the walls and ceilings in the hallway were left blackened by the smoke.
Sutton detectives are appealing for witnesses who have seen anyone acting suspiciously in the area.
The man caught on camera is white and was carrying a large Nike golf umbrella. He was wearing a golf style raincoat, baggy trousers, possibly over the top of other trousers, and thick gloves.
Detective Constable Emily Marshall, of Sutton CID, said: “[We are] keen to hear from members of the public who can help the police investigation into this seemingly motiveless attack.”
“Please come forward if you saw a man of this description in the area of Dower Avenue, Woodcote Avenue or Park Hill Road on November 1 between 6am and 7am, or if you have seen anyone acting suspiciously in the area recently.”
Anyone with information should call 101 or Crimestoppers anonymously on 0800 555 111.