A judge convicted a Chinese-born American Wednesday of stealing trade secrets but acquitted her of more serious charges of economic espionage at a trial that highlighted persistent fears about China pilfering vital information from U.S. companies to bolster its own economy and military.

Software developer Hanjuan Jin was accused of spiriting away more than 1,000 confidential documents from the Motorola Inc. office where she worked before heading to a Chicago airport with a one-way ticket to China.

Among the secrets she carried, prosecutors alleged, were descriptions of a walkie-talkie type feature on Motorola cellphones that government attorneys argued could have benefited the Chinese military.

As the slight, short-haired Jin stood before U.S. District Judge Ruben Castillo, he told her the evidence showed she stole secrets but fell short of proving she did it on behalf of a foreign government or entity.

Later outside court, Jin's attorney told reporters the convictions were disappointing but that the split verdict at least demonstrated his client, a naturalized U.S. citizen, was no agent of China.

"The acquittal acts as a full repudiation ... that Ms. Jin was operating as some sort of spy," John Murphy said. Jin stood next to him without commenting.

Jin, 41, could have received up to 15 years in prison for each of three counts of economic espionage. Despite those acquittals, she still faces up to 10 years for each of the three theft counts for which she was convicted.

U.S. Attorney Patrick Fitzgerald, whose team led the prosecution, told reporters he always prefers a clean sweep of convictions. But he insisted a message was sent and that Jin would still pay a heavy price for her actions.

"When Ms. Jin went to a one-way ticket to China it was a one-way ticket to trouble for her," he said.

The high-profile chief prosecutor said he wasn't sure China would note the verdict, but he hoped U.S. companies would see they can report such crimes and not risk their trade secrets being revealed in court.

"If the Chinese government takes a lesson from this, that'd be great," he said. "But I think we are trying to get the word out to potential people who would steal and the potential victims to come forward and work with us."

Castillo allowed Jin to remain free while she awaits sentencing, which was set for April 18. But he ordered that she wear electronic monitoring and be confined to her Aurora home.

Authorities charged Jin after she was stopped during a random security search at O'Hare International Airport on Feb. 28, 2007. Prosecutors say she was carrying $31,000 and the hundreds of Motorola documents, many stored digitally on a laptop computer, four external hard drives, thumb drives and other devices.

Prosecutors say the former University of Notre Dame graduate student began downloading files at her Chicago-area Motorola office after returning from an extended medical leave just a few days earlier.

In-court testimony at the November trial lasted less than a week, but the complexity of the issues apparently kept Judge Castillo from ruling quickly. Wednesday's hearing lasted less than 30 minutes, but Castillo released a 77-page written opinion afterward.

In that opinion, Castillo wrote that the government hadn't met several requirements to prove economic espionage, including clearly demonstrating that Jin knew the materials she stole could benefit China or its military.

During the trial, prosecutor Christopher Stetler told the court that Jin "led a double life" as a seemingly loyal company worker who was actually plotting to steal her employer's secrets.

Even before returning to Motorola to download files over the several days in February, 2007, prosecutors say Jin had already begun working for China-based Sun Kaisens, a telecommunications firm that government attorneys say develops products for China's military.

But the defense insisted Jin harbored no ill intent and merely grabbed the files to refresh her technical knowledge after her long absence from work. They also said prosecutors overvalued the technology in question, saying the walkie-talkie feature is no longer cutting edge and would have been of little military value.

The conclusion of Jin's bench trial at a federal courthouse in Chicago followed the recent release of a toughly worded U.S. intelligence report accusing China of systematically stealing American high-tech data to the detriment of the U.S. economy.

Before the November report from the U.S. Office of the National Counterintelligence Executive, American officials responsible for tracking the theft of economic secrets hadn't spoken as forcefully in public about their suspicions of China. Beijing has consistently rejected such accusations as baseless.

Out of seven cases related to the U.S. Economic Espionage Act in 2010, six were linked to China, the report said. It added that Chinese intelligence or companies bent on pilfering corporate secrets often seek out Chinese citizens or those with family ties to China.

Motorola Inc. has since become Motorola Solutions Inc., in suburban Schaumburg.


Michael Tarm can be reached at www.twitter.com/mtarm.