Officials said Van Dinh, a student at Drexel University in Philadelphia, lured victims with a request for help in testing software he had written that tracked stock price moves. But that was a subterfuge to be able to install a program called the Beast, which can track every character the user types and relay them to a hacker.
The Washington Post said investigators were alerted by a Westborough, Mass., victim in July. They subsequently traced electronic footprints to Dinh.
The chief of the Security and Exchange Commission's office of Internet enforcement, John Reed Stark, told the Post: "The more elaborate the scheme, the easier it is to catch the bad guy. In all my years here, I've never seen a case like this."
Massachusetts U.S. Attorney Michael Sullivan said the case should alert consumers that installing programs obtained from people they do not know is like "opening the front door of their house to a stranger."
'Happy' fan videos make Pharrell cry [VIDEO]
Pregnant Mila Kunis wins 'Best Villain' at MTV Movie Awards