By - cmeier@meierfire.com 921 Knowledge Quiz Welcome to 921 Knowledge Quiz 1. When investigating the origin of a fire, the expert should use the version of NFPA 921 that was published at the time of the fire. True False Hint 2. NFPA 921 allows investigators to say, "I've eliminated all other accidental causes, therefore this fire MUST be ruled an arson." True False Hint Time's up