A US resident who pleaded guilty to selling StealthGenie spyware online has been handed a $500,000 fine and been ordered to hand over the software's source code to the US government.

In September, the US agency arrested the 31-year-old for selling StealthGenie spyware online after Akbar allegedly sold the malware to an undercover agent two years ago. According to the FBI, Akbar was the controller of spyware sellers InvoCode and Cubitium, platforms for advertising and selling the spyware application online.

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StealthGenie is spyware designed for mobile devices. The app, once installed, can monitor calls, texts and media -- and is able to intercept communication to spy in real-time without user consent. In addition, StealthGenie is able to activate the device to record conversations within a 15-foot radius.

Last week, the Federal Bureau of Investigation (FBI) said Danish citizen Hammad Akbar pleaded guilty to advertising and selling StealthGenie during the case's hearing in the Eastern District of Virginia.

The arrest marks the first-ever criminal case based on the advertisement and sale of mobile device spyware online.

Aside from his $500,000 fine, Akbar was sentenced to time served and order to hand over the StealthGenie source code to the US government.

The FBI assistant director in charge Andrew McCabe said:

"Mr. Akbar is the first-ever person to admit criminal activity in advertising and selling spyware that invades an unwitting victim's confidential communications. This illegal spyware provides individuals with an option to track a person's every move without their knowledge. As technology evolves, the FBI will continue to evolve to protect consumers from those who sell illegal spyware."

According to a promotional video, the spyware has been purchased over 100,000 times.

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