Alert neighbors tipped off police to a sophisticated, million-dollar marijuana growing operation in a quiet Longview neighborhood. Police, who raided the home Saturday, say the operation is among the largest uncovered in the county's history.

Law enforcement officials spent Saturday afternoon cataloguing the more than 300 plants and 40 pounds of harvested marijuana found at 1221 Spruce St off of Cascade Way. All told, the plants and harvested material could sell on the street for at least $1 million, said Detective Sgt. Steven Rehaume of the Street Crimes Unit.

It appears workers were harvesting marijuana every two months, said Detective Brian Streissguth. Rehaume said the investigation is still too young to know if the drug was being distributed locally.

No one was home when police served the search warrant and as of Saturday evening no arrests had been made. Rehaume did not comment on why officers served the search warrant when the home was unoccupied other to say he couldn't control when the plant cultivators came and went.

Police have several suspects, though, including the Seattle-area owner of the home who did not live there but likely was involved, Rehaume said. Police did not release the owner's name, but according to Cowlitz County Assessor's Office records, the home is owned by Thahn H. Tran, who bought it in 2007 for $250,000.

Detectives believe this is part of a well-organized drug trafficking organization hiding in plain sight behind a light blue house with plants in the yard and birdhouses hanging from the roof. Neighbors said they were shocked to have a large-scale criminal activity in what they consider a quiet family neighborhood.

Large grids of electrical transformers with timers were used to divert and use energy before it reached the home's meter and could be billed by the Cowlitz PUD. Such an unusually large consumption of power is often a tip-off to a growing operation. Huge duct work snaked throughout the home's basement, leading to a filter system that greatly reduced the odor from the plants. And rows and rows of large lights with reflective metal umbrella-like wrappings blanketed the ceiling to help the plants grow.

"Other (police) agencies around the state have told us there are double digit numbers of large grow houses in the state similar to this," Streissguth said.

Rehaume said he couldn't comment about whether this operation is connected to several others in Seattle and elsewhere in the state.

Police were first alerted to the house by neighbors reporting suspicious activity and the odor of marijuana, Rehaume said. Investigators began by tracking the home's electrical usage and found that it was "significantly" below the other homes in the neighborhood. Rehaume said at one point the metered electrical usage was only enough to power a refrigerator.

That was enough to get police a search warrant for electrical diversion and theft, and they entered the home 12:15 p.m. on Saturday. The two to five Asian people living in the home reportedly left about 5 a.m. but police do not think they were tipped off about the search.

Once inside, investigators saw the growing operation that occupied the entire basement level and called for an additional search warrant, Rehaume said.

Much of the upstairs was dedicated to mechanics of the grow operation, including the transformer room and the duct system for the air filter system. Streissguth estimated the transformers were using "hundreds of dollars each month in electricity, but there's no way to know because it never reached the meter."

A bed and a few couches were collected in the middle of the living room, which also held what appeared to be a religious shrine complete with candles and oranges arranged along the bottom.

Downstairs, in the 1,700 square-foot space, it was all about the plants.

A large rec room and bar were converted into the main growing area, with mylar wrapping the wall to add further reflection and light for the plants. The temperature even after the massive lights were turned off was in the 80s.

Police found 325 plants as well as 40 pounds of harvested leaves and buds. Depending on quality, marijuana sells for between $2,500 and $4,000 a pound, Rehaume said. A large, mature plant produces about a pound of harvested marijuana.

Investigators, who have been working the case since May 21, said the credit goes to the alert neighbors who paid attention to suspicious activity and contacted police. Among other things, neighbors on Saturday said it was odd that the people living in the house never talked to neighbors and never put out any trash.

"We got really good information from (the neighbors), including license plate numbers, and that helped us out a lot," Streissguth said. "Just being a good neighbor paid off."