Armed with a shovel, a camera and a hypothesis, John Cassidy searches for clues among fire wreckage.

The Colwood fire investigator has 20 years of experience and often begins the hunt as the fire still burns.

During his career Cassidy has attended about 9,000 calls, roughly 1,500 of them fires. He has investigated blazes in dumpsters, tree stumps, fields, vehicles and homes.

B次元官网网址淎nything that burns we have to investigate,B次元官网网址� said the 46-year-old.

Discovering the cause is a bit different from other investigations.

B次元官网网址淧olice investigations of a serious crime or assault leaves behind evidence like DNA or blood. But for us the whole process of a fire is destroying everything,B次元官网网址� explained the Colwood assistant fire chief.

A sleuth on scene, Cassidy has a keen eye for clues such as uneven charring of wood or smoke and heat patterns. He assesses variables including weather and barometric pressure that could impact a fire. More often than not he eliminates potential causes, leading him to the initial spark.

B次元官网网址淭he whole process is narrowing things down,B次元官网网址� Cassidy said. He first searches for the area of origin and then a point of origin.

Sometimes a giant V pattern will pinpoint the location, the pattern marked out in soot and heat damage.

Every fire is different, but often the area with the most damage is where it started, he said. B次元官网网址淓very fire teaches you something different.B次元官网网址�

A few years ago Cassidy attended a fire that started in a bed. Even through he never found the cigarette butt, the residentB次元官网网址檚 burned fingers provided the evidence.

B次元官网网址淎 lot of fire investigators start out helping a fire investigator mucking around at a fire scene,B次元官网网址� he said. B次元官网网址淚 helped sift through all the fire debris and looked for clues.B次元官网网址�