WORCESTER, Mass. — A medical student from China who U.S. authorities say tried to smuggle cancer research material out of the country has been freed on $100,000 bond over the objections of federal prosecutors.

Zaosong Zheng, 30, walked out of U.S. District Court in Worcester, Massachusetts on Friday but will remain under GPS-monitored house arrest, The Telegram & Gazette reported. His passport has also been confiscated.

Zheng was arrested in December at Logan International Airport in Boston with 21 vials of cancer cells in a suitcase he was taking to China, authorities said. Zheng stole the materials from his lab at Harvard-affiliated Beth Israel Deaconess Medical Center, authorities allege. The hospital has fired him.

He’s charged with smuggling goods from the U.S. and making false statements.

The government has opposed his release. Prosecutors argue that he is a flight risk and may be working with the Chinese government, and have raised questions about the source of bail money posted by his wife.

Zheng has not been charged with conspiring with the Chinese government, and a federal judge Friday denied multiple requests from prosecutors that he remain in jail.

Zheng and his wife declined comment outside of court. One of his attorneys, David Duncan, said he does not believe his client did anything wrong.

Federal authorities haven been aggressively going after Chinese researchers in the U.S., some of whom they say work on behalf of the Chinese government to steal the work of American academics.

Last month, a Harvard University professor was charged with lying about his ties to a Chinese-run recruitment program and concealing payments he received from the Chinese government for research.

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