VIDEO: Investigators are trying to determine the cause of three house fires over the weekend -- this as fire prevention week gets underway. Tucson Fire says the way they approach burn patterns is like how a forensics team would approach blood spatter. How a home is burned tells a story to investigators of what happened. "Basically we get called in kind of after the fact of a structure fire," said Rico. Andy Rico is a Tucson Fire Investigator who looked into today's house fire near Oracle and Grant. Rico said his first order of business is searching for hazards.