NAPLES, ITALY -- These con artists work a brilliant scam. Like their colleagues worldwide, they depend upon the greed of their marks.

Bob Arno, brazen videographer and documentarist, used a hidden camera to film their choreography on a street corner last May. His dramatic footage will be featured in the upcoming British documentary, Beware: Conmen.

Stills from the video: Left, a man in a Nike jacket surreptitiously pitches the new Nokia phone.

Below, from left: A man wearing a dark sweater over his shoulders places the Nokia in a box, the box in bag, and continues the negotiation. He refuses the mark's offer and lets mark (in white t-shirt) walk away. Nike man quickly sneaks up and instantly swops the translucent bag containing the phone for an identical bag containing a box of salt, rocks, or a water bottle. Nike man hides the bag containing the phone in his jacket and hurries away.

Seconds later, Sweater man runs back to the mark and agrees to the sale. The mark is delighted by his own negotiation skills. He pays Sweater man in cash and takes the bag, which appears to be identical to the original bag. In the last photo, below, a victim shows his purchase: under newspaper, a water bottle -- squashed to fit the box.

Yes, the grandfatherly seller looks like a decent man; he seemed okay. And it was no surprise that he rejected the mark's ridiculous offer of $80 for a thousand-dollar phone. But that half-second delay was all he needed to make the switch. He said no. The mark turned and walked away. That's when the sleekly seductive chrome Nokia 8880 disappeared under Nike man's jacket and the water bottle took its place.

Directly across the street is the ferry terminal for the Isle of Capri. Those ferry travellers are particularly vulnerable, as are visitors to nearby Pompeii and the Amalfi Coast. Cruise ship passengers, too, are targeted, as the con men know their ships depart shortly after the scam and it's unlikely that the victims will return.

Amazingly, police officers, ostensibly protecting tourists, stood in full force on this very corner. An occupied police van and many officers were in view. This is Italy...