Suspect Stephen Howard is believed to have boarded a train to Fort William after the raid in Whitby, North Yorkshire.
Detectives believe that Howard, 31, fled to Scotland after the intensive police operation last week that was supported by funding from the National County Lines Coordination Centre.
The raid followed a months-long probe into suspected ‘county lines’ drug gangs operating in the Whitby area. The term is used to describe organised crime groups which travel from their home turf to supply drugs in other council areas.
A large quantity of suspected Class A drugs was seized from a car that was heading to Whitby.
The Operational Support Unit then executed search warrants at several addresses in Whitby which led to the recovery of the sawn-off shotgun.
Two people have already been arrested and released under investigation while enquiries continue.
British Transport Police, Police Scotland and West Yorkshire Police are assisting with the search for Howard.
He has also been circulated as wanted to police forces around the country.
Howard is described as white, 5ft 8in tall, short brown hair, green eyes, medium build, and he usually has a trimmed beard.
Anyone with information about Howard’s whereabouts or possible sightings of a man matching his description, are urged to contact North Yorkshire Police on 101, select option 1, and speak to the Force Control Room.
If you would prefer to remain anonymous, please call Crimestoppers on 0800 555 111.
Please quote reference number 12220051395 when providing information.