A source close to the investigation says Ghost Ship founder, Derrick Almena, and tenant, Max Harris, are in custody and they could face charges for involuntary manslaughter.
Authorities say Almena illegally sublet space in the building for artists to live and work. He's also accused of hosting for-profit concerts at the warehouse without a license.
The Alameda County District Attorney's Office is expected to announce the charges sometime today. That fire killed 36 people during a dance party back in December.