Chato, a 2-year-old black lab trained to sniff bombs for the Pierce County Sheriff, was a little confused during his training at Sea-Tac Airport on Tuesday.

He could easily smell the bomb that was hidden in the rolling bag moving through the ticketing area.

The problem was he wasn't sure what to do.

"Following a moving odor is completely different than following a stationary odor," Chato's handler Bill Hultman said.

That's precisely why the Port of Seattle and King County Sheriff's Office are training bomb-sniffing dogs from agencies across the Northwest with new "moving odor" techniques.

Most American bomb-sniffing dogs are trained to sit when they smell a bomb. That approach doesn't work so well when the bomb is moving, such as if a terrorist were rolling a bag through a crowded airport or carrying it inside a backpack.

"We need to be able to follow that moving odor and detect it while it's moving," Hultman said.

Trainers are teaching their dogs to pull them towards the object when they smell an explosive that's contained in something moving, instead of sitting down while the object or person continues to move away.

For the dogs, like Chato, it's just a fun game.

When he smells a bomb, he gets his favorite toy -- a tennis ball.

It didn't take many tries for him to catch on.

When the undercover officer rolled luggage near Chato, he enthusiastically started pulling his handler towards the man and his bag.

It was obvious that Chato smelled something.

And that's when the game began for him -- his handler tossed him his tennis ball.