Yu was charged in federal court Wednesday with 18 counts, including acting as an illegal agent for a foreign government.

Documents said an email showed she was buying parts that would be used on an underwater drone.

The federal indictment said she had worked for Harbin Engineering University from 2002 to 2014. According to documents, HEU conducts research and development for the Chinese government.

She also was running a company called IFour International out of her home.

Yu worked at the University of Central Florida from August 2008 to February 2014, most recently as an assistant in the College of Engineering and Computer Science.

A UCF spokesperson is looking into why Yu left and how much access she had to government research performed at the university.

The charges said she was buying parts, including underwater cables, connectors and sonar from the United States, Canada and Europe and sending them to China, where they were used to make marine submersible vehicles.

Receipts show she spent hundreds of thousands of dollars on the parts over the last few years.

Paperwork also said she denied all of it, saying she worked part time at a university for $40,000 a year.

The indictment notified Yu that the United States intends to forfeit approximately $2,668,648.92, the alleged traceable proceeds of the offenses.

Attorney Mark NeJame is representing Yu. He said the charges sound a lot worse than what they are.

"There is no allegation of espionage, and that's the point we would want to make clear," said NeJame. "There seems to be some technical violations of sending materials, sending parts and not following through with the technical aspects of what the law requires."

Asked why China would need these parts from the United States, NeJame said that's "a very good question and we actually posed the same question."

The case was investigated by the Federal Bureau of Investigation, U.S. Immigration and Customs Enforcement's Homeland Security Investigations, the Internal Revenue Service's Criminal Investigation Division, and the Naval Criminal Investigative Service.