Detectives are appealing for witnesses and information following an arson at a residential building in Prince of Wales Road, Kentish Town.
Police were called on Monday, 27 March, shortly after 19:30hrs to reports of a large fire at the address.
Officers attended the scene along with the London Fire Brigade and there were no reported injuries, however neighbouring homes had to be evacuated.
The cause of the fire is unknown at this stage but it is believed an accelerant was used.
The incident is being treated as arson.
Enquiries have established that two males were seen outside the building shortly before the fire started, with one of them seen to throw something towards it.
They then made off towards Haverstock Hill.
The males are described as being in their late teens, both around 5ft 4ins in height and of slim build.
Both were wearing dark tops and trousers or jogging bottoms. One of the males had white stripes down the leg of his trousers or bottoms. He also had red coloured trainers and was wearing a light blue Nike rucksack.
Detectives from Central North CID are investigating. No arrests have been made and enquiries continue.
Detective Constable Dean Puzey, Central North CID said: “Due to the prompt response of police and London Fire Brigade surrounding houses were evacuated. Luckily no one was injured and the fire was brought under control quickly.
“We are keen to hear from anyone with information on this incident and in particular those who witnessed the two males near the address around the time the fire started. If anyone took images or captured footage of these males then we ask you make contact us with us as soon as possible.”
If you have any information about the fire or saw the males near Haverstock Hill, then please call Central North CID police on 020 8345 0195 or via 101, tweet @MetCC or call Crimestoppers anonymously on 0800 555 111.