A house in the Foreglen, near Dungiven, where police uncovered an estimated £400,000 of drugs, was the subject of what police are describing as a suspicious fire.
Shortly after 11.30pm on Thursday, the NI Fire Service attended a blaze at a house at Farkland Road.
Damage was caused to the conservatory of the house, which is under construction, police said.
Inspector Jenny Hudson said: “The cause of the fire was being treated as suspicious.”
Insp. Hudson appealed for information from anyone who saw suspicious activity or unknown cars in the area on Thursday evening.
Sinn Fein Councillor Tony McCaul said: “Police are treating this fire as suspicious, and certainly I would condemn those responsible. If anyone saw anything out of the ordinary or they think they saw something suspicious I would urge them to contact the police.”
Cannabis plants worth an estimated £400,000 were seized by neighbourhood officers from Limavady in the two-storey property, which is just off the main Derry to Dungiven Road, on October 23, 2014.
At that time, a 25-year-old male was charged with drugs offences, while two other men aged 52 and 58 who were arrested were subsequently released pending further enquiries.
Polive have appealed to anyone with information to call the police non-emergency number, 101, or by calling the Crimestoppers Charity anonymously on 0800 555 111.