(AP) – Two sagging Pacific Gas and Electric Co. power lines made contact and ignited a blaze last year that killed four people and injured a firefighter in Northern California, fire officials said Tuesday about the latest wildfire to be blamed on power lines.

Strong winds caused the lines to touch, creating an electrical arc that sent molten material onto dry vegetation below, the California Department of Forestry and Fire Protection said.

The blaze in Yuba County that started on Oct. 8, 2017, scorched 15 square miles (39 square kilometers) and destroyed 264 structures.

Cal Fire said the report on their investigation has been forwarded to the Yuba County district attorney.

It was one of several wildfires that swept through Northern California that month, killing 44 people and destroying more than 5,000 homes. State officials say insured damages alone topped $9 billion.

Fire investigators have blamed PG&E equipment for 12 of last year’s wildfires in wine country, including two that killed a total of 15 people.

In eight blazes, investigators said they found evidence of violations of state law and forwarded the findings to county prosecutors.

Authorities have not determined fault for the Tubbs Fire, the most destructive in state history that destroyed thousands of homes and killed 22 people in Sonoma County.

PG&E is facing dozens of lawsuits from insurers that have spent billions settling insurance claims from homeowners.