Security expert

(FORTUNE Magazine) -- BOB ARNO, author and pickpocket scholar

Bob Arno has spent the last 30 years trotting the globe to capture pickpockets on film and to study their technique.

"A great pickpocket executes moves that could be on par with a Russian ballet dancer's. He is usually somewhere between 38 and 55. He's a career criminal. He also has the psychological insight to understand and read victims. He is physically very agile - fast and good with his hand. There's nothing clumsy about him. He will get a certain style or technique that he perfects over a 10-year period. He likes to work in crowds. That means entering or exiting the doors of a subway at rush hour. It could be Rome, New York, or London. He steps in and makes the contact, and then it seems as if he made a mistake and walks out again. He may stand in a subway where there's movement or in a crowded elevator. The thief will reach up as if he's losing his balance with his left hand, and he will reach out to hold on to a door or grab something to steady himself. His arm comes under the chin of the victim, and that stops the victim from being able to dip down with his head. It also blocks the view. Then he reaches in under his own arm in the same direction and lifts the inside jacket pocket. That is very complicated and takes significant coordination.

"Knowing where the wallet is, is key. The good operators use what's called fanning. Maybe in a bar, 20 minutes earlier, they brushed into the victim. It's light like the wind. Like the rustling of leaves. And doing that, they know the wallet is in the top pocket on the left. They sense whether it is a wallet or coins or a pen or a diary.

"I call the typical victim a 'pappy.' That's slang for a victim who is 40 or 45 years old. He is at least 15 pounds overweight. His pants are not going to be tight Armani jeans. They're going to be loose, businessman jeans. They are usually businessmen--successful--and they practically always look the same."

HOW TO Pick a Pocket*

1. After casing the scene, the thief enters a crowded area like a subway or an elevator to find his prey.

2. His arm comes under the chin of the victim, and he uses his right hand to reach inside the coat.

3. Using a jacket or newspaper to distract the victim, the thief grabs the wallet and makes off.

*Do not try this. It is illegal.