Russian Harvard researcher Kseniia Petrova detained at Boston airport

Kseniia Petrova, a Russian biologist working at Harvard Medical School, was stopped by US Customs and Border Protection officers at Boston's Logan airport on 16 February 2025. She was returning from a trip to France.

Petrova was carrying frog embryos intended for scientific research. Officials said the samples had not been properly declared, and her visa was cancelled. She was then held in immigration detention, a custodial system run by the US immigration authorities.

Petrova's lawyers said the specimens were non-hazardous research material used in her work on cell biology and that she had no intent to smuggle anything. She has said she feared returning to Russia because of her opposition to the war in Ukraine and her earlier participation in protests.

The case drew wide attention among scientists and in the press, as it came amid tighter US immigration enforcement and concern over how researchers from abroad were treated. It later led to criminal proceedings over the alleged smuggling of the embryos, the case now dropped.