cannabis greenhouse operations have been found in Telemark, Buskerud, Hedmark and Østfold counties

Seizures of cannabis plants that could be used to produce hashish and marijuana were made on the island called Kråkerøy, just outside Fredrikstad, and at Kongsberg in Buskerud over the weekend.The raid on a house in Kongsberg resulted in the fourth seizure of what police are calling indoor "plantations" in just a week. Around 400 cannabis plants were found in the house, which was being rented out.
A Vietnamese man was arrested at the scene, and was to face charges .The Kråkerøy and Kongsberg seizures were the 14th and 15th in recent months in southern Norway. Other cannabis greenhouse operations have been found in Telemark, Buskerud, Hedmark and Østfold counties, and several have involved Vietnamese tenders like at the house in Konsberg.
Police acknowledged over the weekend that they think the cannabis operations are linked, and the national crime unit Kripos has been called in to aid local investigations."We've noticed that many of these cases bear similarities," Atle Roll-Mathiesen told newspaper Aftenposten. "We've gotten involved, to look at the links between them."The tenants of the house on Kråkerøy had engineered and built what police call "professional" greenhouse-type facilities that monitored watering and fertilizing of the plants. Geir Kristiansen of the Fredrikstad Police Station said the operation seemed "very organized."