Tokyo (CNN) -- As Japanese authorities widen their investigation into ties between financial institutions and organized crime, an investigative reporter says the current allegations have left with a sense of "déjà vu."
"In 2004, Citibank (Japan) lost their private banking license because they were allowing yakuza to do many complex transactions," Jake Adelstein, author of "Tokyo Vice" and an expert on Japan's mafia -- known as the yakuza -- told CNN. "They got spanked in 2009 for failing to update their databases and allowing yakuza to do business with them again.
The Financial Services Agency (FSA), the country's financial regulator, will send inspectors to Japan's three largest banks -- Mizuho Bank, Tokyo Mitsubishi UFJ Bank and Sumitomo Mitsui Bank -- to "review over their corporate governance, legal compliance and overall risk management," said Hiroki Kato, director of the Inspection Bureau of the FSA. The on-site inspections are scheduled to begin next week.
All three banks declined to comment on the review when contacted by CNN.
Ties to gangs
Mizuho has already come under scrutiny after 54 executives, including the bank's president, were punished after it was revealed an affiliate made more than $2 million in loans to people with ties to organized crime.
Yakuza is the name given to Japan's organized crime syndicates. Adelstein -- the only American who has worked a crime beat for the Yomiuri Shimbun, Japan's largest newspaper -- has called them "Goldman Sachs with guns" because of the financial prowess and sometimes brutal means.
"The yakuza have been tremendously successful because they can work out in the open," Adelstein told CNN. "They have business cards, they have office buildings. People know who they are -- they have fan magazines and they have a lot of money."
Members are said to follow a strict code of discipline -- and often sport full body tattoos. The biggest and wealthiest yakuza gang -- the Yamaguchi-gumi -- is said to number nearly 40,000 members. Robert Feldman of Morgan Stanley Japan once called the Yamaguichi-gumi "Japan's largest private equity group."
Belonging to a yakuza gang itself is not a crime. But members are known to engage in drugs, prostitution and gambling. After recent crackdowns by Japanese authorities, yakuza are making more strides into white-collar crime, experts say.
"So if you have a lot of money and a lot of information and you can use blackmail and extortion to do insider trading it can make quite a tremendous financial force," Adelstein said. "Yakuza have tremendous political connections and they have a lot of information to blackmail people."