A Chinese-born American woman has been jailed for four years after stealing millions of dollars in trade secrets from Motorola.

Hanjuan Jin, a software engineer for the company for nine years, was convicted after U.S. District Judge Ruben Castillo described her as a 'soft-spoken, unassuming woman who carried out a very purposeful raid on the company in the dead of night.'

Jin was stopped during a random security check trying to board a flight to China from a Chicago airport in February 2007, with prosecutors revealing she was carrying $31,000 and over 1,000 confidential Motorola documents stored on a laptop, external hard drives and thumb drives.

Despite Jin claiming to have took the files to refresh her knowledge following a long absence from work, Judge Castillo ruled the 41-year-old to be spying for China, ordering Jin to report to prison on October 25, while paying a $20,000 fine and receiving three years of supervision upon her release.

Judge Castillo said it was important to send a clear message to deter others with access to trade secrets from passing on crucial information.

"In today's world, the most valuable thing that anyone has is technology. ... The most important thing this country can do is protect its trade secrets," Castillo says.

"It is a raid in no uncertain terms. It is a raid to steal technology. ... You conducted this raid in the dead of night when you knew that there was a lesser chance you'd get caught."

Possessing confidential Chinese military documents, Jin was also identified as an employee of Chinese telecommunications company Sun Kaisens, which U.S. government attorneys say develops products for China's military.

Yet Jin was acquitted of the more serious charge of economic espionage, with Judge Castillo believing evidence fell short of proving beyond a reasonable doubt that she stole the information to ultimately benefit the Chinese military.

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