Judge Drops Frog Embryo Smuggling Case

A federal judge in Boston dismissed all criminal charges against Kseniia Petrova on Wednesday. The decision grants a motion filed by the government to drop the case against the Russian-born scientist. Petrova had been indicted last year on three counts: concealment of a material fact, false statement, and smuggling goods into the United States.

Petrova conducts cancer research at Harvard Medical School. She was questioned by customs officers at Boston Logan International Airport in early 2025 while returning from a vacation in France. During that trip, she stopped at a laboratory in France that specialized in splicing superfine sections of frog embryos. She obtained a package of these samples for her research.

U.S. District Judge Leo Sorokin issued the dismissal without holding a hearing. Sorokin, who was nominated by former President Barack Obama, accepted the government's recommendation to end the prosecution. The dismissal follows a series of legal setbacks for the federal government in this case.

The legal battle began to shift in April when a federal judge ruled that a customs officer had improperly canceled Petrova's visa. Petrova had been briefly detained by immigration officials and feared deportation to Russia. Her lawyers subsequently filed a motion to dismiss. They argued that the government was prosecuting her selectively and vindictively, claiming the charges were filed only after it appeared she would win her immigration case.

On Tuesday, U.S. Attorney Leah Foley filed the motion to dismiss. Foley cited developments in the case and an assessment of her office's priorities and resources. She stated that the resource costs of continuing the prosecution outweighed the public interest in resolving it. Foley also noted that the defendant's claims of vindictive and selective prosecution were meritless.

Foley pointed to an April court ruling that granted Petrova broad discovery rights. This ruling required the government to provide documents related to comparable cases and Customs and Border Protection policies. Foley wrote that the government must supply information on passenger encounters involving undeclared items. This includes cases regardless of how items were carried or the strength of evidence regarding fraudulent intent.

Petrova told The Associated Press in an interview that she did not realize the items needed to be declared. She stated she was not trying to sneak anything into the country. One of her attorneys, Daniel Marx, issued a statement regarding the dismissal. Marx said the Department of Justice never should have brought the highly unusual smuggling prosecution against a talented scientist.

Marx emphasized that Petrova sought to advance medical research into aging that could benefit everyone. He described the scientific samples as inert, non-living, and non-toxic frog embryos that never posed a danger to anyone. A spokesperson for the Department of Homeland Security had previously said Petrova was lawfully detained after lying to federal officers about carrying substances into the country.

The Department of Homeland Security includes Customs and Border Protection. A spokesperson for the department stated earlier this year that the Trump administration was committed to restoring the rule of law and common sense to the immigration system. The dismissal ends the criminal case, though the immigration implications of the initial visa cancellation remain separate from the criminal charges.

The next step in the process is not specified in the court filings. The dismissal resolves the three counts of indictment against Petrova. She remains employed at Harvard Medical School where she continues her work in cancer research. The decision marks the end of the criminal proceedings that began with her arrest at the airport.