While Cal Fire crews continue to work the Lopez Fire burning outside of Arroyo Grande, Investigators believe they have found the cause. Authorities say an improperly extinguished campfire is to blame and they want to talk with the person responsible. The Lopez Fire broke out at around 2 Saturday afternoon near Upper Lopez Canyon Road. Firefighters are getting an upper hand on the fire that has scorched 220 acres. It was last reported to be 70 percent contained.