Federal Judge Dismisses Frog Embryo Smuggling Case Against Harvard Scientist in Boston

A federal judge in Boston on Wednesday granted a government motion to dismiss all criminal charges against Kseniia Petrova, a Russian-born scientist at Harvard Medical School. The dismissal resolves a case in which Petrova was accused of smuggling frog embryos into the United States.

Federal District Judge Leo Sorokin, who was nominated by former President Barack Obama, issued the order without a hearing. The decision clears Petrova of one count of concealment of a material fact, one count of false statement, and one count of smuggling goods into the United States. She had been indicted on these counts last year.

The legal trouble began in early 2025 when Petrova returned to Boston Logan International Airport from a vacation in France. During her trip, she had visited a laboratory that splices superfine sections of frog embryos and purchased a package of samples for her cancer research. While passing through the customs checkpoint, officers questioned her about the items. A Department of Homeland Security spokesperson said earlier this year that she was lawfully detained after lying to federal officers about carrying substances into the country.

The situation escalated in April when a federal judge ruled that a customs officer had improperly canceled Petrova’s visa. The cancellation stemmed from the same incident at the airport. Petrova had been briefly detained by immigration officials and expressed fear of being deported to Russia and imprisoned there. Her attorneys subsequently filed a motion to dismiss, arguing that the government was prosecuting her selectively and vindictively. They contended that the criminal charges appeared only after it looked like she would win her immigration case.

In a statement, attorney Daniel Marx said the Department of Justice should never have brought the prosecution. He described the samples as inert, non-living, and non-toxic, noting that they posed no danger to anyone. Marx said Petrova only sought to advance medical research into aging that could benefit everyone. Petrova told The Associated Press in an interview that she did not realize the items needed to be declared and was not trying to sneak anything into the country.

On Tuesday night, U.S. Attorney Leah Foley filed the motion to dismiss. She stated that the decision was based on developments in the case and an assessment of the office’s priorities and resources. Foley wrote that at this stage, the resource costs of continuing the prosecution outweigh the public interest in its resolution. She also stated that the defendant’s claims of vindictive and selective prosecution were meritless.

Foley cited an April court ruling that granted Petrova broad discovery in support of her selective prosecution argument. The ruling required the government to provide documents related to comparable cases, as well as Customs and Border Protection policies and procedures. Foley wrote that the government must supply information pertaining to any number of passenger encounters involving undeclared items. This includes cases regardless of how the items were carried, the presence or absence of planning, or the strength of the evidence of fraudulent intent.

The dismissal ends the criminal process for Petrova, who was conducting cancer research for Harvard Medical School. The case had drawn attention from the Trump administration, with a DHS spokesperson earlier stating that the department was committed to restoring the rule of law and common sense to the immigration system. The department includes Customs and Border Protection.