Gery Shalon and Ziv Orenstein, two men accused of orchestrating the largest-ever theft of customer data from a U.S. financial institution, were extradited from Israel to the U.S. late last week, according to the U.S. Attorney's Office in the Southern District of New York.

The defendants face serious charges of computer hacking, securities fraud and identity theft. Appearing in U.S. court for the first time, the men pleaded not guilty to the crimes, including breaking into the networks of various financial institutions and brokerage firms, including J.P. Morgan Chase & Co., according to the Wall Street Journal.

Shalon and Orenstein allegedly perpetrated these hacks as part of a series of cybercrimes and financial schemes. Specifically, they are accused of manipulating the trading of public stocks through deceptive spam email campaigns and prearranged stock trading, then using fake identities and shell corporations to launder profits. Another prime suspect, U.S. citizen Joshua Aaron – believed to reside in Russia – has yet to be arrested.