(Adds details of findings, background on fire)
By Steve Gorman
LOS ANGELES, March 13 (Reuters) - The devastating Thomas Fire that killed two people and destroyed more than 1,000 structures northwest of Los Angeles in December 2017 was sparked by power lines owned by Southern California Edison Co , the Ventura County Fire Department said on Wednesday.
An investigation of the fire's origins found that high winds blew Edison power lines into one another, creating an electrical arc that "deposited hot, burning or molten material" into dry vegetation on the ground, setting off the blaze, the department said in a statement.
The 70-plus page report came a day after prosecutors in four Northern California counties said they had found insufficient evidence to criminally charge PG&E in a deadly October 2017 firestorm ignited by that utility's power lines.
PG&E, seeking bankruptcy protection in the face of billions of dollars in potential civil liability from those fires, was cited for safety code violations stemming from eight blazes for which it was investigated.
A Ventura County Fire spokeswoman declined to say whether investigators had found any code violations by Edison in connection with the "line slap" blamed for the Thomas Fire.
The wind-driven blaze burned for nearly 40 days as it threatened the towns of Santa Paula, Ventura, Ojai and Fillmore, scorching nearly 282,000 acres in the Ventura and Santa Barbara county foothills along the Southern California coastline.
At its height, as many as 9,000 fire and emergency personnel battled the blaze, with crews from across the Western United States sent to help.
Mudslides unleashed by torrential rains drenching the fire-ravaged area in January swallowed dozens of homes and killed at least 20 people. (Reporting by Steve Gorman in Los Angeles; editing by Jonathan Oatis and James Dalgleish)