Helicopters assisted Southern California Edison workers Wednesday in dismantling an idle transmission tower central to the investigation into the cause of the Eaton fire that destroyed more than 9,000 structures and left 18 people dead.

The chief executive for SCE’s parent company told investors recently it is becoming more apparent that the privately held utility may be liable for the fire, absent evidence to the contrary. The leading theory is that a tower that had been dormant for more than 50 years became reenergized