Sacramento, Calif.-- Cal Fire investigators release the cause of four Northern California wildfires in what officials are calling 'The October Fire Seige' of 2017.

All four from Butte and Nevada Counties, are being blamed on tree branches coming in contact with power-lines. 

In Butte County, the La Port Fire burned over 8,000 acres near Bangor and destroyed 74 structures.  Cal Fire says there was no violations of state law.

However, Cal Fire says the Honey Fire that burned 76 acres near Paradise, was caused by inadequate clearance between trees and power lines. Cal Fire says it's PG&E's responsibility to maintain that clearance, not homeowners.

They released the same cause for the 'McCourtney Fire' and the 'Lobo Fire' in Nevada County.

Cal Fire says the October 2017 Fire Seige involved more than 170 fires. These four fires are the first fire investigations to be complete. 

The investigation now heads to the district attorney's office for review.