Ellie a specially trained sniffer dog and she helps experts work out if fires were caused by arson attacks.
She's a springador - part Labrador and part springer spaniel - and here her handler Mat Dixon explains what she does.
How are fire dogs useful when you're investigating a fire?
Ellie works with Fire Investigation Officers who will go out and look at suspect fires.
How are the dogs chosen?
They're from a variety of backgrounds. Before Ellie was trained as a Fire Investigation Dog she was a working gun dog. To be a fire dog the dogs have to have a keen sense of smell and be athletic. They also have to be inquisitive with a bold and outgoing personality because they have to be happy working on sites where fires have happened.
What do the dogs look for?
We take Ellie to 'cold' fire scenes, which is when the fire has been put out. She is often a key part of the investigation. The dogs sniff for anything that an arsonist would use to start a fire, like flammable liquid. That includes things like petrol, diesel and lighter fluid. She'll be looking for any traces of liquid like this.
Dogs like Ellie are also used to search an area. For example, when an arsonist has fled from a scene they might throw a petrol can into a bush. If a can has been left in this way, Ellie will find it and experts can then get fingerprints and DNA from it, which helps with catching and identifying arsonists. These dogs are also used to search the houses, vehicles and clothing of suspected arsonists.
How do the dogs train?
The whole training process is based around play. The dogs are rewarded for finding substances with play and praise - usually a tennis ball they get to play with. Ellie was trained for about six months, and then had to pass a special exam, to prove she was at the standard where she could work at fire scenes. Some dogs are faster or slower - most are trained in six to nine months.
How good is her nose?
It's impossible to say how sensitive her nose is - but scientists have said that it's thousands of times more sensitive than a human's. Ellie's nose is so sensitive that it can outperform lab equipment.
Does Ellie wear special protective clothing?
Ellie wears protective equipment including special dog shoes and a brightly-coloured harness. The harness has three main uses - it tells her that she is working and looking for the start of a fire, it helps you see where she is on the site and it allows us to attach a search line to make sure that she is safe and can be stopped from going into dangerous areas, like a collapsed part of the floor.
The special shoes protect her paws from being cut by sharp things including nails, wood and broken glass. These paw-protectors come in a number of sizes, and have Velcro fastenings and tough rubber soles for protection and grip. Ellie wears a medium.
What's Ellie like as a dog?
She likes socks and teddy bears and anything small and furry. If there's a spare pair of socks on the floor she will pick them up, bring them back and drop them at her handler's feet. She's a permanently happy dog who loves showing people what she does and how clever she is! When she's not at work she's a family dog, and when she retires from working she will carry on living with her handler's family but as a pet.