by Andria BorbaBy Andria Borba

HAYWARD (KPIX 5) — Oakland police officers have taken five people into custody following a robbery at a marijuana warehouse in Hayward.

The Oakland Police Department’s Operation Ceasefire team had a group of people under surveillance for the past month in connection with a string of burglaries and robberies at cannabis clubs and dispensaries around the Bay Area.

READ MORE: San Francisco 49ers Special Teams Spark 13-10 Upset Of Green Bay Packers To Advance To NFC Championship Game

During the Wednesday night robbery – which happened at a warehouse, not a dispensary – an employee was beaten and locked in a safe. The employee later declined medical treatment.

OPD served warrants in three cities on Thursday: Oakland, Hayward and Stockton, where the gang’s hideout was.

READ MORE: UPDATE: Wind-Whipped Wildfire Near Big Sur Forces Evacuations; 'Some Pretty Surreal Fire Behavior'

“This has been a long term investigation with multiple locations. I will say that the evidentiary value in terms of cameras have immensely assisted in our investigation,” said Oakland police captain Ersie Joyner III.

KPIX has learned it’s not just Alameda and San Joaquin counties involved; the investigation will also lead to dispensary robbery and burglary cases in San Mateo and San Francisco counties as well.

MORE NEWS: Protesters, Counterprotesters Face Off at San Francisco 'Walk for Life' Rally

The case has been handed over to the Alameda County District Attorney’s office, who will prosecute the cases. Information about the suspects identities is expected to be released on Monday.