HAYWARD (KRON) — The Hayward Police Department announced Wednesday that it had served a search warrant on an illegal marijuana grow operation.

The narcotics unit served the search warrant at the warehouse on Diablo Avenue on Thursday, June 4 as part on an ongoing illegal marijuana distribution investigation.

Because of the size of the warehouse, and because there was a camera surveillance system, the police department’s SWAT Team served the warrant and secured the area.

As of the result of the search warrant, police arrested three people. 28-year-old Manh Tran of Hayward, 21-year-old Troy Tam of Oakland and 22-year-old Tony Hoang of Alameda were all charged with felony marijuana cultivation and sales.

Sergeant Ryan Cantrell said that this is he largest marijuana grow bust in the history of the Hayward Police Department.

Police said that the 44,000 square foot warehouse had been converted into a large marijuana factory.

When police searched the warehouse, they found marijuana in all stages of growth from seedlings to plans ready for harvest.

The electrical systems had been dangerously by-passed with major illegal connections that powered an elaborate hydroponic watering system, lighting system and ventilation system, said police.

Included in the suspected operation was a harvesting and packaging room, living quarters and a security system.

Police think that the suspected operation cost more than $100,000 to build.

The seizure of almost 13,000 marijuana plants has a conservative street value of approximately $15 million dollars, according to police