NEW ORLEANS ? A New Orleans jailor has called game, set, and match on six people who tossed drug-filled tennis balls into his prison yard.

Sheriff Marlin Gusman had netting strung up around the recreation yard walls a couple years back to ward off smugglers.

But the tennis balls ? which can be hollowed out to hold illegal cell phones, weapons and drugs ? kept coming.

"They have all the time in the world to think about how to do things," Gusman said Friday. "Our job is to stay one step ahead of them."

So he set up an undercover operation which netted the six civilians and seven inmates captured orchestrating the scheme.

They were booked Thursday on various charges of introducing marijuana and illegal cell phones into city's jails.

The sheriff, who says that he was never very good at tennis in his leisure time, says he and his deputies have to bring their best game to work to match wits with the city's prisoners.

Inmates orchestrated the smuggling scheme using legal pay telephones inside the jails -- which are monitored by deputies, the sheriff said.