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AURORA, Colo. — Investigators looking for missing 6-year-old David Puckett are using bloodhound dogs to assist in the search.

The child has been missing since Saturday. Since then, bloodhound teams from Jefferson County have been attempting to track his scent in hopes of finding the boy.

“It’s just amazing what they can see with the scent,” handler Paula Bindrich said.

Bindrich has been a certified handler with Search and Rescue Dogs of Colorado for 16 years. Her yellow Labrador retriever Tuuli is her third air scent dog.

She said it’s easy to understand how sensitive a dog’s nose is if you think about a cake. Humans smell the finished baked product, while dogs can still smell each ingredient individually.

That heightened sense is critical for search and rescue teams. They can pick out a single scent as far as five miles away.

“We’re looking at things visually and you can miss things, and we’re also listening for things. We can miss that too in high winds or whatever. Dogs are using their nose,” Bindrich said.

Bloodhounds near Puckett’s home are trying to follow the path the boy might have walked. It is difficult work for the dogs because the boy has been in the area many times in the past.

“It’s also kind of hard for them though when they’re in an area where the people have been living because they’ve been working around and walking and so there’s a lot of scent that they have to filter through to try and say this is old, this is new,” she said. “But they can do it.”

Scent trails can last up to a month in undisturbed areas. The more people walking around contaminating an area, the quicker scent trails degrade.

In a heavy traffic urban setting, bloodhounds can pick up trails up to twelve hours after a disappearance.

The Aurora Police Department has asked volunteer search crews to stay out of the search area so the bloodhounds can work.

“The more they have to filter, the more work for them and the more distractions,” Bindrich said.

Search and rescue dogs begin training as puppies. Handlers start with simple hide and seek tasks.

“And then we put a scent article in front of them and they start thinking that smells like where mom was. And we just keep expanding it,” Bindrich said.

A scent article is something that smells like the missing person. Ideally, it’s a smelly sock, hat or jacket. However, search and rescue is not always that easy.

“I have used door handles before,” Bindrich said.

In that instance, the dog had to pick out the smell of the missing person, while disregarding the smells of everyone else who had recently touched the door handle.

The dog remembers the scent and when it finds a match, it alerts the handler.

“They have like a Rolodex of scents in their head,” Bindrich said. “They save lives and help bring families back together again.”

All of the canine search and rescue teams in Colorado are volunteers. Dogs and handlers have to be certified in order to work a scene.

“We do this on our own because we want to do it. We want to help,” Bindrich said.