Xi Xiaoxing (Photo/Xinhua)

WASHINGTON, Sept. 11 -- The U.S. Justice Department on Friday dropped charges against a Chinese-born professor who had been accused of sharing sensitive U.S. technology with China, after an "embarrassing" mistake was found about the case's key evidence, media here reported.

The so-called sensitive technology involved a device called "pocket heater," which is used in semiconductor research.

Xi Xiaoxing, an American citizen and chairman of Temple University's physics department, allegedly sent schematics for such a device to scientists in China and was therefore arrested in May.

But when the evidence was shown to independent experts, including one of the device's co-inventors, it was found that the diagram, which the Justice Department said was for the pocket heater, was for a different unrestricted device.

"It was an embarrassing acknowledgment that prosecutors and FBI agents did not understand -- and did not do enough to learn -- the science at the heart of the case before bringing charges that jeopardized Dr. Xi's career and left the impression that he was spying for China," the New York Times wrote.

"But Dr. Xi's case, coming on the heels of a similar case that was dismissed a few months ago in Ohio, raises questions about whether the Justice Department, in its rush to find Chinese spies, is ensnaring innocent American citizens of Chinese ancestry."

About a dozen FBI agents, some with guns drawn, stormed Xi's home in the Philadelphia suburbs in May. Xi was then handcuffed and taken away as his two daughters and his wife watched. He was also demoted from his position as the chairman of the physics department at Temple University.

"I don't expect them to understand everything I do," Xi, 47, who came to the United States in 1989, told the the New York Times. "But the fact that they don't consult with experts and then charge me? Put my family through all this? Damage my reputation? They shouldn't do this. This is not a joke. This is not a game."

"If he was Canadian-American or French-American, or he was from the UK, would this have ever even got on the government's radar?" Xi's lawyer, Peter Zeidenberg, asked. "I don't think so."

It's the second time this year the Justice Department has falsely accused Chinese-born scientists of spying on the United States.

In March, U.S. federal prosecutors dropped charges against Sherry Chen, an employee of the National Oceanic and Atmospheric Administration.

Chen, whose given name is Xiafen, was accused of stealing sensitive information from a database for the nation's dams and lying about the breach.

The case against Chen backfired as 22 U.S. Congress members urged the country's Attorney General Loretta Lynch in May to investigate whether there is a practice of targeting federal employees based on their race or national origin.

"There's been a history of discrimination against Asian Pacific Americans, and the recurrent theme is one of suspicion," House Representative Ted Lieu said during a press conference at that time.

Information of Xi Xiaoxing (Photo/Xinhua)