PARADISE VALLEY, AZ - Troy Duncan knows his way around a fire.
He has been an arson investigator for years and said his colleagues working the Paradise Valley case have their work cut out for them.
"Fire investigations in general and the kinds of investigations that involve fires are generally some of the hardest investigations to complete," he said.
The Mesa firefighter says fires can destroy a lot of material at a crime scene, but not everything.
"There's always something left. There's always something for us to collect, analyze and process," he said.
Duncan said investigators will sift through the scene, and gather anything that could be a clue.
"Fire evidence is everything that can be put into a can or a bag and sent into the lab to be analyzed," he said.
Duncan says it can take weeks for labs to process evidence, which requires patience, but says doing it right the first time is key to catching the person who started the fire.
"You can never ever go back to the beginning, so as you go, you want to be sure you cover those bases," he said.