Investigators said they found three encrypted CDs in the couple’s luggage that contained documents on a submarine propulsion system, a solid-state power switch for ships and a PowerPoint presentation on the future of power electronics.

Mak’s wife, Rebecca Laiwah Chiu, pleaded guilty last year on the eve of her trial to one count of acting as a foreign agent without registering with the U.S. government. She is serving three years in federal prison and will be deported upon release.

His brother, Tai Mak, pleaded guilty last year to conspiring to violate export control laws in exchange for a maximum sentence of 10 years in prison. Tai Mak’s wife, Fuk Li, pleaded guilty to aiding and abetting the violation of export control laws and received three years of probation.

Yui “Billy” Mak, the son of Tai Mak and Fuk Li, pleaded guilty to aiding and abetting the violation of export control laws and was sentenced to time already served. The three will also be deported.