CHICAGO – Meet Chris. He has a nose for trouble.

The frisky, yellow Labrador retriever is the newest sleuth to join the crime-fighting team in the Chicago office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

With his sensitive and highly trained nose, Chris doesn’t just sniff out a hidden bomb. He finds a place where explosives used to be stored – even after they have been removed.

“Chris can smell things that we can’t even see,” says Donald J. Sorrano, assistant special agent in charge of ATF’s Chicago office.

On a recent morning, ATF put on a demonstration.

Chris roamed a large room within the ATF’s Chicago office, sniffing.

He stopped at a black valise propped against a wall. His handler, veteran ATF Special Agent John Boskovich, had hidden a revolver in it. There were no shells in the pistol and therefore no visible gunpowder for Chris to smell.

But there were traces. And that was enough.

Next Chris parked himself quietly beside a closet door. Behind the door were two sticks of dynamite.

Both times he was rewarded with a snack.

Some 130 ATF trained dogs similar to Chris are in service nationwide. Many have been trained by the ATF and turned over to local police departments, including one in the Kane County community of Yorkville.

Yorkville Chief Harold Martin says his department’s dog has gone to the scene of threatened school bombings and other potential trouble. He also has sent the dog and his handler on loan to other communities.

“These dogs are fantastic,” Martin says. “Especially in these times, I think we are going to be using them more and more.”

Chris started life in an upstate New York prison as part of the Puppies Behind Bars program. Inmates help law enforcement and build up time off for good behavior by raising puppies in their cells. Experts say the program, which exists in several states, has been a stunning success.

Chris is also a graduate of the 20-week training program at the ATF’s canine school at Front Royal, Va. As much as $80,000 is invested in training each dog. As a final exam, the dogs, all labs, must detect 20 separate explosives, two of which he has never been exposed to before.

That’s possible because the dogs are taught to sniff out each of five distinct families of explosives and the two unfamiliar scents are still from explosives in a family that the dogs know.

Chris has been on the road lately. He helped maintain security at this summer’s Republican National Convention. And soon, Chris and handler Boskovich will be heading for Iraq for a hitch doing security duty there.

Chris is following the paw steps of a black lab Boskovich formerly handled. That dog did three hitches in Iraq.

The ATF makes it plain that while its dogs become experienced air travelers they are never kept in portable kennels where airlines keep some animals. The dogs sit at the feet of their handlers while airborne.

Boskovich’s black lab – who has now retired – was brought to Northern Illinois University after the fatal shootings there in February that left six dead including the gunman.

The dog indicated there was something suspicious about a piece of luggage in the gunman’s hotel room. It contained ammunition and holsters.