US prosecutors seek to drop case against Harvard Medical School researcher from Russia

The US Department of Justice has asked a federal court in Massachusetts to dismiss the criminal case against Kseniia Petrova, a Russian researcher at Harvard University charged with smuggling frog embryos into the United States, according to lawyer Igor Slabykh.

Prosecutors want the case dismissed with prejudice, meaning the same charges could not be brought again. The court must still rule on the request.

In the filing, prosecutors said that continuing the case would take up significant time and divert resources from more important federal priorities. “At this stage, the resource costs of continuing this prosecution outweigh the public interest in its resolution,” the Justice Department wrote. Slabykh noted that the court had earlier granted a defence motion to disclose the circumstances of Petrova’s detention.

Petrova was detained in February 2025 at Boston’s airport after returning from a scientific conference in Paris with samples of frog embryos. She has said she did not know the biological materials had to be declared and never intended to bring them into the country covertly.

Her visa was nonetheless revoked, and she was sent to an immigration detention facility. She was charged with smuggling in May and released on bail in June. The Justice Department said it would seek to send her back to Russia.

In April 2026 a federal court ruled that US Customs and Border Protection had unlawfully cancelled Petrova’s visa, finding that the agency lacked legal grounds to do so. The ruling concerned her visa cancellation and did not resolve the separate criminal smuggling case.

Petrova has said she feared deportation because she could face political persecution at home. Since Russia’s full-scale invasion of Ukraine, she has taken part in various antiwar protests and started a petition demanding Vladimir Putin’s resignation.