A federal grand jury has indicted a Chinese American engineer and his wife and brother on charges that they acted as agents of a foreign government without prior notification of the U.S. attorney general. Authorities say the indictment relates to the alleged theft of sensitive U.S. government information.

Tuesday's federal indictment charges Chi Mak, his wife, Rebecca Laiwah Chiu, and his brother, Tai Wang Mak, with one count each of failing to register as agents of a foreign government.  The three were the subjects of an earlier criminal complaint concerning the theft of sensitive government information.  Sixty-five-year old Chi Mak and his wife, who is 62, are both naturalized U.S. citizens.  His brother, who is 56, is Chinese and is a U.S. resident.

In an affidavit filed in connection with the earlier complaint, authorities say Chi Mak, an engineer with the California defense contractor Power Paragon, took home computer disks with information on quiet propulsion systems for Navy warships.  The affidavit says he copied the data onto CDs with the help of his wife, and then delivered the information to his brother, who encrypted it and planned to take it to China.

The three were arrested October 28th, along with Tai Wang Mak's wife, Fuk Heung Li.  Assistant U.S. Attorney Gregory Staples tells VOA Ms. Li will be charged with marriage fraud, although she was not named in Tuesday's indictment.

Authorities have said that Tai Wang Mak planned to travel to Guangzhou, China, to meet a contact.  He was taken into custody with his wife at Los Angeles International Airport.

The charge of failing to register as a foreign agent carries a possible penalty of 10 years in prison.  The three defendants will be appear before a judge in Santa Ana, California, Monday.