Mourners place flowers and candles during a vigil honoring those who died in a warehouse fire in Oakland, California on December 5, 2016.

Investigators said Tuesday a warehouse fire in Oakland that killed 36 people did not appear to have been set intentionally and may have been caused by a refrigerator or other electrical appliance.

Details about a possible cause emerged as fire crews nearly completed their search for bodies in the most lethal building fire in the U.S. in more than a decade. The death toll remained at 36 and was not expected to go higher.

Tearful family members visited the scene and exchanged hugs hours after the founder of the arts collective that used the warehouse stood near the gutted building and said he was "incredibly sorry."

"Everything that I did was to make this a stronger and more beautiful community and to bring people together," Derick Ion Almena told the "Today Show" on NBC.

Almena said he was at the site to put his face and his body in front of the scene, but he deflected blame for the blaze, saying he signed a lease for the building that "was to city standards supposedly."

The fire broke out during a dance party Friday night in the cluttered warehouse. It had been converted to artists' studios and illegal living spaces, and former denizens said it was a death trap of piled wood, furniture, snaking electrical cords and only two exits.

