Helicopters assisted Southern California Edison workers Wednesday in the dismantling of 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 that 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 in the high winds through a phenomenon called “induction.”

“While SCE has not conclusively determined that its equipment was associated with the ignition of the Eaton fire, it is also not aware of evidence conclusively pointing to another source of ignition,” said Pedro Pizarro, president and CEO of Edison International, the parent company of Southern California Edison, in a recent earnings call with analysts and shareholders.

A separate state and county investigation into the cause of the fire that tore through Altadena is ongoing.

As part of its own internal investigation, SCE is dismantling two dormant towers for further analysis in collaboration with investigators for more than 130 lawsuits blaming SCE for sparking the fire.

The tower that has generated the most scrutiny is Tower 208, the shorter of three towers where the fire is believed to have originated in the foothills above Altadena.

The utility has spent the last few weeks inspecting the transmission lines in Eaton Canyon as part of its investigation, focusing on the Mesa-Sylmar line, which has been idle since it was damaged in an earthquake in 1971. The actual power lines were spooled up and taken away for analysis.

The leading theory into the cause of the fire is that the electromagnetic field of a nearby active line potentially reenergized the idle tower, which then sparked the blaze through arcing on a transmission line or through an exposed grounding wire, according to lawsuits.

With a blue sky backdrop on Wednesday, May 7, a sky crane helicopter removed the top of Tower 208 and flew it to a designated area, where it was to be loaded onto a truck and taken to a warehouse in Irwindale for further study. The helicopter returned later in the day for the bottom half. In days to come, SCE crews will remove a second tower on the Mesa-Sylmar line.

Representatives for plaintiffs in the lawsuits were invited to inspect the dismantled towers in the field and at the warehouse, said SCE spokesperson David Eisenhauer.

“It’s an important moment because it is all part of our commitment to a thorough and a transparent investigation,” Eisenhauer said. “It gives us the opportunity to look very closely at the equipment.”