Two Israeli citizens were among three people indicted at a New York court for their part in a complex security fraud plot, which included computer hacks of banking giant JPMorgan Chase Co., among other financial institutions.

A joint operation by the FBI and Israeli law enforcement agencies resulted in the arrests of four men in Israel and Florida over the scam, which was on such a grand scale that JPMorgan initially believed the hacks were the work of the Russian government.

A fifth co-conspirator is believed to be still at large.

According to Bloomberg, two of those indicted – including one currently living in Israel – are charged with securities fraud relating to the scheme, in which they planned to pump up the value of low-volume stocks.

Another two people arrested in Florida were charged with “running an unlicensed money-remitting business related to the scheme,” it said.

The men charged have been identified as Israelis Gery Shalon and Ziv Orenstein, and US citizen Joshua Samuel Aaron, who resided in both the US and Israel.

The plot reportedly involved mass email campaigns and prearranged trading in what is known as a “pump and dump” scheme, whereby stocks are artificially inflated in value to be sold on at a massive profit.

At least five stocks were “pumped” over 2011 and 2012, though there may have been others, Manhattan federal court heard Tuesday.

The elaborate criminal enterprise also spanned Russia and Ukraine, with two of the accused meeting with another co-conspirator from New Jersey in Kiev.

JPMorgan have yet to issue a response to the latest developments.