Police are appealing for witnesses following what appears to be a deliberate act of arson at an address in Pelham Road, Lindfield, on Saturday (August 10).
At around 2am a lit firework was put through the letterbox, which exploded and scorched the door.
PC Dave Jones from the neighbourhood response team said: “This could have caused more serious damage and fortunately the occupants, who were in bed asleep, were not injured.
“Officers have been making house to house enquiries in a bid to find out who may have been responsible for this mindless act of criminal damage.
“If you have any information that could help officers with their enquiries then please call 101 quoting serial 1601 of 10/8 or alternatively leave an anonymous message with the independent charity Crimestoppers on 0800 555 111.”