Federal judge dismisses charges against Harvard scientist accused of smuggling frog embryos

A federal judge dismissed criminal charges against Kseniia Petrova, the Russian-born Harvard scientist accused of smuggling frog embryos ​into the United States.

The order from District Judge Leo T. Sorokin in Massachusetts came Wednesday, a day after federal prosecutors filed a petition to drop the charges against Petrova.

In the filing, prosecutors said they made the move following an order from a federal magistrate judge in April allowing Petrova to obtain evidence supporting her claims that she was being vindictively ​prosecuted.

Prosecutors stated in their petition that while they thought Petrova’s claims of vindictive and selective prosecution were “meritless,” providing evidence to the contrary would mean disclosing “non-public information” about the operations and investigative techniques of U.S. Customs and Border Protection.

Daniel N. Marx, Petrova’s attorney, told NBC News in a statement Wednesday that “throughout these proceedings, Ms. Petrova has shown tremendous courage, and we are relieved that this chapter of her terrible ordeal is now over.”

Marx said the Department of Justice “never should have brought this highly unusual ‘smuggling’ prosecution” against his client, whom he described as a talented scientist at Harvard University determined “to advance medical research into aging that could benefit everyone.”

Petrova, a biomedical researcher, was taken into custody by immigration authorities at Boston’s Logan Airport in ​February 2025 after returning from Paris. Her J-1 scholar visa was canceled following the detention, and she was later placed into immigration proceedings. Earlier this year, a judge in Vermont ruled that Petrova’s visa was unlawfully canceled.

In May 2025, federal prosecutors brought a criminal case against Petrova while in immigration detention, charging her with smuggling goods into the United States after officers at the airport found clawed frog embryos, paraffin slides and other samples in her possession that Petrova has insisted are part of her research.

Marx told NBC News on Wednesday that “her handling of scientific samples — inert, non-living, non-toxic, frog embryos — never posed any danger to anyone.”

He added that two federal judges decided that “the suspicious circumstances” surrounding Petrova’s case warranted further investigation into whether the Department of Homeland Security and the DOJ “unfairly targeted” his client.

“Although that important question will not yet be answered, we are pleased the DOJ has finally reached the appropriate conclusion and asked the court to immediately dismiss all criminal charges against Ms. Petrova,” Marx said.