By May of that year, people in the group had created fake power of attorney documents. That gave Mr. Phillips control of four of the dormant accounts, Adam Zion, an assistant district attorney, said in court on Monday. This allowed Mr. Phillips to withdraw much more money than the daily A.T.M. limit, up to $9,500 at a time, through a teller.

Image From left, Jonathan Francis, Dion Allison and Gregory Desrameaux, three of the men charged in the case. The fourth, Kery Phillips, is still at large. Credit... Brooklyn District Attorney's Office

In another example of the scheme, in February 2013, according to the indictment, Mr. Allison created a bank card for one account. That May, at a Chase branch on Flatbush Avenue, Mr. Phillips turned in fake power of attorney documents giving him control of the account. The same day, prosecutors said, Mr. Phillips withdrew through a teller $49,929.91 — everything that remained — from the account.

JPMorgan Chase has already faced accusations of fraud among staff members this year. In April, an investment adviser, Michael Oppenheim, was charged in Federal District Court in Manhattan with stealing $20 million from seven of the bank’s clients.

Also in April, another employee, Peter Persaud, who worked at a Chase branch in Brooklyn, was accused of selling customer data — including account numbers, Social Security numbers, addresses and dates of birth — to an informant and an undercover officer. Mr. Persaud was charged with fraud and identity theft in Federal District Court in Brooklyn.

Lauren Ryan, a spokeswoman for JPMorgan Chase, said the company had been “working closely with the authorities and the Social Security Administration” in the current fraud case.

The four men listed in the current indictment have been charged with conspiracy, grand larceny and falsifying business records.

On Monday, Mr. Allison was arraigned before Justice Cassandra M. Mullen in State Supreme Court in Brooklyn. Mr. Zion, the prosecutor, said that Mr. Allison searched for and maintained the targeted accounts, and issued and used some of the cards.