NAPLES, Italy (AP) — Luigi “Giggino’’ Nocerino once stalked tourists through the tight alleys of this southern Italian city, snatching bags and valuables to fuel his drug addiction.

Now he looks after his former prey, escorting them through bad neighborhoods and giving tips on how to avoid muggings and where to eat the best pizza.

Nocerino is one of 70 former convicts, including muggers, drug traffickers and con artists, hired by authorities to guide tourists through the art-rich but crime-plagued city and use their inside knowledge of the local underworld to keep visitors safe.

Officials say the six-month experiment that began in May is succeeding in reducing petty crime and preventing the ex-cons from falling back into old habits or joining the ranks of the Camorra, the powerful mob syndicate that runs global drug rings out of Naples.

“I used to hunt for tourists. How things have changed,’’ Nocerino marvels, recalling how he spent more than 10 of his 43 years serving prison terms for drug-related offenses.

Nocerino and his fellow guides roam tourist-filled areas, like the historic center of Naples or its port, wearing bright yellow vests identifying them, in somewhat mangled English, as “Operator for the Urban Tourist Assistance.’’

Some speak basic English and Spanish but most use Italians’ expressive hand gestures to get the message across. They walk around in groups accompanied by a supervisor, usually a private security guard, who knows them and reports on their performance.

Their job can include pointing the way to a monument, helping tourists negotiate a cab fare or walking them to a specific pizzeria or a pastry shop. The service is free and tips are not encouraged.

Giovanni Aspride, a 53-year-old former counterfeiter, said he and his colleagues usually wait for tourists to approach them, though they may come forward if somebody seems desperately lost or to tell a visitor to remove a gold watch or tuck a wallet in a safer pocket.

Though their criminal record does not have to be revealed, the guides are not shy about discussing it if it comes up in conversation.

On a busy shopping street on Tuesday, Aspride pointed an American couple just off a cruise ship toward baroque churches in the area, then checked that they weren’t wearing any jewelry that could attract unwanted attention.

“You OK,’’ he told them in broken English.

The tourists were unfazed when told Aspride had served time.

“It’s a great way to reintegrate them into society,’’ said Brooke Cervine March, 37, of Santa Fe, New Mexico. “Everybody deserves a second chance.’’