Canines in blue

COATESVILLE, Pa. (WPVI) -- Four legged police officers put their skills to the test Wednesday in Coatesville.

Teams of K9s and handlers from across the region are competing in the US police canine association trials.

They're put through drills to detect narcotics, explosives, and human remains, to name a few.

The chester county sheriff's office is the only agency with at least one dog in every specialty.

The winners advance to the national trials in Philadelphia in June to compete against the best in the world.