The United States arrested and charged an Iranian semiconductor scientist with violating U.S. export laws by buying high-tech U.S. lab equipment, The Associated Press reported on Thursday.

The report cited prison records showing the U.S. is holding 54-year-old Seyed Mojtaba Atarodi, a microchip expert and assistant professor at Tehran’s prestigious Sharif University of Technology, in a federal facility in Dublin, California.

Friends told AP Atarodi was detained December 7 after stepping off a plane in Los Angeles.

U.S. law enforcement officials, the report said, have declined to discuss any aspect of Atarodi’s case, and records indicate the charges have been sealed. Atarodi arrived at a bond hearing in federal district court in San Francisco on Thursday, but the judge closed the courtroom except to attorneys and members of the family.

A spokesman for Sharif University, however, told AP Atarodi has been charged with buying instruments from the United States. The university official spoke only on condition of anonymity because of the potential repercussions of the case.

Atarodi is listed as the author or coauthor of dozens of scientific papers dealing with microchip technology, AP said, though none appears to be explicitly related to military work. U.S. officials in the past have targeted suspected export control violators dealing in so-called dual-use technology, which can have both civilian and military applications.

The Sharif University spokesman said Atarodi was engaged only in civilian research, saying, “The fact of the matter is that he was just a professor, and he was trying to buy some equipment for his lab, and the equipment was very, very simple, ridiculously simple stuff that anybody can buy.”

Atarodi’s arrest comes two weeks after Professor Mostafa Ahmadi Roshan, an Iranian nuclear scientist, was killed in a car bombing in northern Tehran.

Iran blamed Israel for the assassination, warning that it would “bring the war to Israel and beyond” in response. 

There have been several similar attacks on Iranian scientists over the past few years targeting those involved in the country’s nuclear development and military activities. A missile expert died last November in a blast at a military base southwest of Tehran. The scientist was a member of the Revolutionary Guards.