The tenant of a two-story residential house “just made a bad decision to use fire instead of insecticides to kill the spiders,” Lee Wilding, deputy fire marshal with the Fresno Fire Department, told ABC News.

“The tenant used a torch like a handheld propane torch to kill the spiders that were around the base of the residential structure, and in doing so some flame from the torch went in between some of the cracks and the siding and into the interior of the wall,” Wilding said. “It started a small fire within the wall that then traveled up into the attic through the wall space and into the attic to cause a larger fire.”