US Attonery for the Southern District of New York has filed a case against two US banks, Citibank and Bank of New York (BNY) Mellon, at the Manhattan federal court and requested permission to issue John Doe summonses for the banks for hiding records of US citizens’ accounts at Swiss bank Zuercher Kantonalbank (ZKB).

According to the filing, Zurich-based ZKB offers private banking services to clients around the world including US taxpayers through correspondent accounts at Citibank and BNY Mellon.

The filing also said that though the two banks are accused of any wrong doings, the banks were used by ZKB as correspondents to provide offshore banking services to US taxpayers, who have failed to show their ZKB accounts to the IRS and income earned on those accounts.

Florida-based Private law practitioner and former federal prosecutor Jeffrey Neiman was quoted by Reuters as saying that with John Doe summonses, what the US is trying to do is figure out who accessed their undeclared Swiss bank account money, and did anyone access it in a way that flowed through US banks.