A Harvard University medical student and cancer researcher who allegedly tried to smuggle stolen scientific material into China has been charged and will be held without bail, a federal judge in Boston ruled Tuesday.

The 29-year-old Chinese student, Zaosong Zheng, was found with 21 vials in his luggage as he prepared to board a flight at Logan International Airport bound for Beijing on Dec. 9, court documents stated. The vials were wrapped in a plastic bag and hidden inside a sock.

Zheng was a cancer researcher who earned an educational visa with Beth Israel Deaconess Medical Center last year, according to The Boston Globe. Beth Israel fired Zheng after he was arrested for allegedly making false statements about the items in his bags. His visa was also revoked.

The vials appeared to contain a brown liquid and were being tested to confirm whether they were stolen from the lab. If so, Zheng could face more charges.

“Zheng’s appointment to [Beth Israel] was not an accident; he was knowingly gathering and collecting intellectual property from [Beth Israel] possibly on behalf of the Chinese government,” FBI agent Kara Spice said in a court affidavit.

Some of the vials included a colleague’s work Zheng said he had replicated without the lab's knowledge, according to court documents.

Zheng said he had intended to "immediately" head to his lab in China to work with the vials and publish a paper taking credit for the findings, according to the documents.

U.S. District Court Magistrate Judge David H. Hennessy granted a request from federal prosecutors to detain Zheng until he can be tried, acknowledging his connections to the Chinese government made him a flight risk, the Globe reported.