Cal Fire said transmission lines owned and operated by the San Francisco-based utility started the November 8 fire in the Pulga area that almost destroyed the town of Paradise in the Sierra Nevada foothills.
The inferno killed 85 people, scorched 153,336 acres and destroyed 18,804 structures, according to Cal Fire.
The investigation identified a second ignition sight near the intersection of Concow Road and Rim Road.More news: Protestors arrested after Sydney Harbour Bridge stunt
California authorities said Wednesday that power lines owned and operated by the Pacific Gas & Electric Corp.
A Cal Fire official says investigators found PG&E violated utility law and forwarded their conclusions to the local district attorney to determine if criminal charges should be filed.
Shares of San Francisco-based PG&E initially fell 3.1 per cent in after-hours trading following release of the California Department of Forestry and Fire Protection (Cal Fire) statement announcing the findings of its investigation. The fire spread through Pulga into the communities of Concow, Paradise, Magalia, and the outskirts of east Chico.
Paradise Mayor Jody Jones told The Associated Press she was not surprised that PG&E lines had sparked the blaze.
PG&E had reportedly considered cutting power in the area because of the high winds and unsafe conditions but chose not to do so.More news: John Wick: Chapter 3 - Parabellum Review: 8 Ups & 2 Downs
The utility filed for Chapter 11 bankruptcy in January as it faced tens of billions of dollars in potential costs related to deadly California wildfires.
The city of Paradise - population 27,000 - was almost wiped out as residents evacuated and their homes and vehicles were engulfed in flames.
The company was supposed to present its reorganization plan by the end of May, however, it recently asked for a six-month extension. He said the utility's request continues to show it lacks an urgent focus on improving safety.
At an oversight hearing in the state Assembly, PG&E's new CEO Bill Johnson said he's committed to making the company accountable to customers and victims.
Newsom and lawmakers are working on proposals around utility liability for wildfires that could affect the bankruptcy.More news: Gerald Schwartz: The man behind Onex and the WestJet deal