A Chinese scientist was apprehended upon her arrival at Detroit airport, marking the second incident within a short span involving the alleged smuggling of biological material into the United States, as reported by authorities on Monday.

This scientist stands accused of previously shipping biological material related to certain worms to a laboratory at the University of Michigan. The FBI, in a court filing, stated that this type of material necessitates a government permit for importation.

“The guidelines for importing biological materials into the U.S. for research purposes are stringent, but clear, and actions like this undermine the legitimate work of other visiting scholars,” John Nowak, who leads field operations at U.S. Customs and Border Protection, was quoted as saying.

The scientist was questioned and arrested Sunday, following her arrival on a flight originating in China. She is in the process of completing an advanced degree at Huazhong University of Science and Technology in Wuhan and had planned to spend a year completing a project at the University of Michigan.

Her shipments, including one concealed within a book, were intercepted and examined by authorities last year and earlier this year, according to reports from the FBI. The court filing does not make clear whether the FBI believes the biological material posed any inherent risk.

U.S. Attorney Jerome Gorgon Jr. voiced concerns, saying that such smuggling “threatens our security.”

Michael Shapira, a biologist at the University of California, Berkeley, after reviewing the court filing, said, “It doesn’t strike me as something dangerous in any way. But there are rules for shipping biological material.

Both sides of this issue present compelling arguments. Additional context comes from a recent event where the government charged two Chinese scientists with conspiracy to smuggle toxic fungus into the U.S. One scientist was turned away at the Detroit airport and sent back to China last year, while the other, a researcher at the University of Michigan, is currently in custody.

The scientist involved in the recent incident is also currently in custody, and a bond hearing is set for Wednesday.