(Grants Pass, OR)  --  Oregon State Police say they've shut down an illegal marijuana operation near Grants Pass.  Troopers seized more than 31-hundred plants in five large greenhouses.  Three people, one adult and two juveniles, who live in New York, were arrested.  Police also seized a semi-automatic gun with no serial number.  There were multiple code violations on the property and Jackson County will take enforcement action against the property owner that could result in it being closed for a year.