By Oren Liebermann,

GLOUCESTER TOWNSHIP, Nj. (CBS) — The partnership between police officer and K9 comes with practice. And its product is confidence.

“You spend a lot of time, put a lot of effort into these dogs,” says Gloucester Township Patrolman Chris Gerace. “And when it works out, just like your kid, you’re proud.”

On Saturday at 2 a.m., Officer Gerace and his K9 Arrow were called into action. Police were chasing two dirt bike riders on Jarvis Road. Police say they were riding in the middle of the roadway with no helmets and no lights.

The bikers split up, and one headed to Lilley Elementary School, where his bike stalled. He left the bike and ran into the woods. Minutes later, Arrow was on his scent.

“He was pulling me through the woods almost half a mile,” says Gerace. “We tracked the guy through the woods.”

Arrow, a 3-year-old Belgian Malinois, found 20-year-old Kevin Kelly, Jr. hiding in a ravine. Police say Kelly gave himself up.

“As soon as he saw Arrow crest the hill and come into the valley, he said he knew it was over,” Gerace says.

But Kelley had one more act of defiance. Police say he kneed Arrow in the chest. Arrow will only attack for three reasons. If he is told to, if his handler is threatened, or if he is threatened.

Arrow tore into the suspect’s knee, only letting go when Gerace told him to.

“We’re always proud of our police K9 teams in Gloucester Township,” says Captain Anthony Minosse. “And Arrow his proven himself on more than one occasion.”

Police say they are still looking for the second suspect. They say Kelly is not cooperating.