$10M cash, 500K marijuana plants seized in Bay Area's largest-ever bust

Alameda County sheriff's detectives say an 18-month investigation has resulted in the seizure of upwards of $10 million in cash, up to 500,000 marijuana plants, 6 tons of processed marijuana valued at $42 million, and a cache of weapons. 

The bust marks the largest-ever illegal growing operation in the Bay Area, and among the largest ever in the state, Sgt. Ray Kelly said.

The cultivation operation was sophisticated, and the sheriff's office says the marijuana quality was the best they've ever seen.

The operation involved over a dozen locations scattered throughout the East Bay, Kelly said. Specifically, these included Oakland, San Leandro, Hayward and Castro Valley.

Photo: Alameda County Sheriff’s Office.

In all, Kelly says a total of 500,000 square feet of commercial real estate was dedicated to the operation. In the Bay Area, the cost of renting this much commercial space is several million dollars per month. The average size of each location was around 70,000 square feet, but some were smaller, such as 10,000 square feet, Kelly said. 

RELATED: Union City police bust marijuana growing operation valued at up to $11 million

Inside, the operation was streamlined and the equipment was plentiful. 

"Some of the locations had corporate style furniture, break rooms. They had wine, refrigerators with thousand-dollar bottles of wine that they would just sip on. Televisions, vending machines, break rooms," Kelly said.

The people responsible weren't named, but Kelly says the organization is well connected within the state, and possibly in the nation. "These people have connections to foreign nationals, Kelly said.

Photo: Alameda County Sheriff’s Office.

Detectives say the operation resulted in tens of millions of dollars in profits. It's not clear how long the operation was successfully running.

There were also a "tremendous amount" of weapons seized, at least a dozen. These included handguns, rifles, and shotguns. 

Seven people considered to be the "main individuals" of the operation are in custody. There are others that deputies are searching for as well, Kelly said. None of the seven were identified. "I'm sure they'll bail out because they have millions of dollars to post bail," Kelly said.

In response to a question about destroying marijuana, which is used as medicine by residents in California, Kelly said the Sheriff's Office has a duty to intervene in the illegal operation. Besides not paying taxes and license fees, the illegal operation also threatened the safety of the communities it was operating in.

Photo: Alameda County Sheriff’s Office.

"This is not legal. This this does not meet the thresholds and guidelines as prescribed by the state of California. I don't think that we would take on the liability of vouching for this cannabis and wanting it to go into our community. So it needs to be destroyed. The courts have agreed and have ordered it to be so," Kelly said.

Besides the plants and the cash, detectives seized various infrastructure items used to grow the plants. This includes specialized lighting, power generators to run the lights, and other miscellaneous supplies commonly used to grow marijuana.

"The enormity and complexity of this illegal grow operation cannot be expressed in words or pictures, it’s unbelievable," Kelly said.

At one of the locations in Oakland, detectives say there was well over $1 million in electrical generators alone. "These locations pull off so much power that they have to create their own energy, Kelly said.

Photo: Alameda County Sheriff’s Office.

Detectives will remain on the scene for the next several days. The various scenes contain an "enormous amount of evidence."

"We've been working this for two days. Our people are tired. They're exhausted. It's a lot of work. So much so that we had to go and get chainsaws and gas-powered hedge trimmers to cut down all the plants because otherwise it would have taken us weeks and weeks to cut all this down by hand," Kelly said.

ALSO: Illegal marijuana grow operation found in Hayward's Garin Regional Park

Photo: Alameda County Sheriff’s Office.

Duncan Sinfield is a reporter for KTVU. Email Duncan at duncan.sinfield@fox.com, and follow him on Twitter.