A man has been arrested following investigations into a fire in a South Oxhey home at the weekend.
Police launched an investigation after a house in Gosforth Lane was left badly damaged when a large fire broke out on Sunday, January 5.
A 24-year-old man has since been arrested on suspicion of arson, cultivating cannabis and abstracting electricity.
Fire crews from Watford, Garston and Rickmansworth were called to the blaze at around 8pm.
Watch commander Dave Elliott, from Watford Fire Station, said the fire had taken hold of the roof by the time firefighters arrived.
Hertfordshire Constabulary said cannabis plants were found in the property and the arrested man has been questioned and released on bail until February 15.