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Rosie Investigates Arson

The smell of smoke still hangs thick in the air when Dennis and Rosie arrive at the scene of the fire. Rosie’s nose probably picked up the scent several blocks away and she’s intrigued. But it’s not the smoke that drives Rosie. Rather, she wants to know what caused the smoke.

Rosie is an Ignitable Flammable Liquid Detection Canine, better known as a detection canine or, more simply, an arson dog. She retired in May of 2012 after spending 8 1/2 years working side-by-side with her handler Dennis Johnsen, the Arson Unit Chief of the Santa Clara County Fire Department (SCCFD).

During an arson investigation, Rosie and Dennis search a fire scene in a specific pattern in an attempt to locate areas of suspicion. Most arson fires are started with one of about eight common accelerants, all of which Rosie is trained to identify. She is also trained to “alert” by sitting when she catches the scent of one.
While searching, Dennis closely watches Rosie as other slight changes in her behavior may also signal an alert. When she points her nose to the ground (another form of alert), Dennis knows that she has found a concentrated area of accelerant. He takes a sample which is further analyzed and confirmed by the Crime Lab.

The reports and evidence that Rosie and Dennis produce are used to make arrests and are also used in court proceedings. “In essence,” Dennis explains, “we are law enforcement officers that work for the Fire Department and we’re on call 24/7.”

During Rosie’s career, she also assisted the Bureau of Alcohol, Tobacco, and Firearms (ATF) National Response Team, as well as other agencies. With the SCCFD alone, she searched over 1,000 fire scenes resulting in convictions of over 30 suspects for arson or other related crimes. “Without her nose, I would say we would have only made a few of the arrests,” says Dennis. Of the 400 to 600 fires per year in Santa Clara County, nearly 200 are due to arson.

Time after time, Rosie’s nose was amazing. In one investigation, Rosie alerted in several areas of a house fire, even though the areas had not burned. Curious, Dennis asked Rosie to repeat her search, where she again alerted. Further analysis revealed a small amount of accelerant that had not ignited, providing evidence from areas that would have most likely been overlooked had it not been for Rosie’s attention.

In another case, Rosie helped identify a suspect by alerting to the presence of gasoline on a pair of pants, even though the pants were submerged in a bucket of water. In yet another incredible find, Rosie alerted to gasoline on the clothes of a homicide victim, though the body had been buried for eight months. The Crime Lab confirmed her alerts. Dennis remarks, “We would not have been able to detect anything without the nose.”

A Yellow Labrador, Rosie was born in 2001. Her journey began with Guiding Eyes of New York, but she quickly switched careers to become an arson dog. Like many arson dogs, Rosie was trained at the ATF’s training facility in Virginia. The ATF requires that potential arson dogs have a calm demeanor and possess a strong food drive combined with the ability to detect the scent of food – often common traits of a Labrador Retriever. During ATF’s evaluation of her food drive/scent detection, a piece of kibble was placed on top of a van’s front tire.

Rosie circled the van and quickly found the tiny kibble. In her eagerness to gobble it up, she knocked it off the tire into the van’s suspension. Relentlessly pursuing the kibble, she proceeded to get caught in the suspension! She passed the evaluation and underwent four weeks of intensive training with ATF, then was joined by Dennis for an additional six weeks of training. Then Rosie accompanied Dennis back to California where they began working together in late 2003.

Rosie is a passive-alert, food reward-trained canine, which means that she eats only when she finds an accelerant. The food-reward portion of the training was easy, according to Dennis. Once Rosie figured out that she got to eat when she found a certain scent, she never forgot that scent. And once her nose crossed paths with a scent plume, it was nearly guaranteed that she would find the source.

Surprisingly, one of the more challenging parts of working with an arson dog was when Rosie wasn’t actively working an investigation. Her daily food intake amounts to making 30 “finds” per day. Since Rosie only eats when she makes a find, it was Dennis’ job to place accelerant in various locations for her to locate.

As part of her ongoing training, the locations had to vary without being repetitive in order for Rosie to really work to find the accelerant and be rewarded with her kibble.

“I had to get pretty creative,” notes Dennis.

Now that Rosie is retired, she lives with Dennis and his family and no longer has to work for her food. What is Dennis’s job like without Rosie? “It’s harder and more time consuming for all involved,” says Dennis. “We have to take maybe ten samples versus one or two that Rosie would identify.”
Plus… “The Labrador nose is, without a doubt, more sensitive than the Crime Lab instruments, and a lot more fun to have around of course.”

Claudia Bidwell is a certified dog lover who (with her dog) leads a weekly group dog walk, visits an assisted-living facility with a team of therapy dogs, and helps coordinate other dog-related get-togethers in the San Jose area. She and her husband were adopted by Black Lab mix Poppy J and part-time dog Macy.

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