About 30 bar patrons in the Kabukicho entertainment district of Tokyo appear to have been robbed since autumn after being given alcohol until they were drunk in a ploy organized by several bars in the area, The Yomiuri Shimbun newspaper has learned. The police believe a sophisticated operation involving at least five bars has pocketed more than $530,000 by forcing customers to drink themselves unconscious, and then stealing their cash cards. According to sources, one bar would ply a customer with drink and take him to a nearby ATM to watch him type in the PIN number, while the next would keep the customer drinking and steal his cash card to withdraw money. The Metropolitan Police Department is investigating the cases as drugging-robberies. A 50-year-old company employee from Nerima Ward who had been drinking heavily in Kabukicho, died last week after a bar manager and three others robbed him and left him on the street early that morning. The man reportedly had been enticed to drink a large amount of vodka mixed with shochu and other beverages at a bar called Mimatsu. His ATM card was then stolen, and the man was abandoned on the street. The bar's manager, Mitsuko Ogawa, 73, and three others have been arrested on suspicion of drugging-robbery. According to investigation sources, two women who appeared to be bar staff cozied up to the man while he was drinking and accompanied him when he went to withdraw cash from an ATM at a nearby convenience store. The women watched the man punch in his PIN number and then apparently later stole the cash card and used it to withdraw more money.