DOJ Drops Frog-Embryo Smuggling Case Against Harvard Researcher Kseniia Petrova; Dismissal Filing Includes Internal 'Frogs' Emails

Federal prosecutors in Boston have dropped their smuggling case against Kseniia Petrova, the Harvard Medical School researcher charged after she brought frog embryo samples through Logan International Airport in February 2025, and a judge dismissed the indictment with prejudice on Wednesday.

U.S. District Judge Leo T. Sorokin allowed the government's request in an electronic order on Nov. 4, writing that the United States "seeks to dismiss this prosecution with prejudice and explains its reasons for doing so." A dismissal with prejudice means the charges cannot be brought again.

The Digital Free Press read the government's five-page notice of dismissal, filed Tuesday, and the internal emails prosecutors attached to it, as well as the court's Oct. 8 ruling on discovery that preceded the dismissal.

Why Prosecutors Say They Dropped the Petrova Case

The notice, signed by U.S. Attorney Leah B. Foley, says dismissal is appropriate "based on developments in this case and an assessment of the office's priorities and resources." It also says Petrova's claims of vindictive and selective prosecution "are meritless."

Prosecutors wrote that a court-ordered discovery process would require the government to turn over information about "any number of passenger encounters involving undeclared items that could be considered comparable," along with some non-public U.S. Customs and Border Protection procedures. "At this stage, the resource costs of continuing this prosecution outweigh the public interest in its resolution," the filing says.

What the Internal Emails Show

To rebut the claim that the case was retaliatory, the government filed internal communications. According to the notice, one exhibit quotes an Immigration and Customs Enforcement message about Petrova's messages with her supervisor before her arrival: "Interesting to see advance discussion of the plan to smuggle. We'll have the field engage." The notice says Homeland Security Investigations headquarters then asked its Boston office "to determine if there are any viable charges" and to review whether her supervisor "was complicit with the smuggling attempt."

The third exhibit is a May 2025 email chain with the subject line "RE: Frogs," dated about a week before the sealed criminal complaint was filed on May 12, 2025. In it, Assistant U.S. Attorney Nadine Pellegrini wrote to an HSI agent: "I think, in addition to smuggling and obstruction, the importation is a violation under 18 USC Section 42. It's a misdemeanor but anything that gives us an opportunity to explain why this deception is important is helpful." The chain copies a U.S. Fish and Wildlife Service address.

The notice describes the prosecutor as "a 27-year veteran of the office with experience prosecuting wildlife smuggling" and says "no internal communications support" the defense's view that Petrova was charged because of her immigration habeas case, her statements to the press or her J-1 visa status.

The Court's Earlier Discovery Ruling

The dismissal came less than a month after Sorokin denied the government's appeal of an order by Magistrate Judge Judith G. Dein requiring prosecutors to produce discovery and their grand jury instructions on the smuggling charge.

In that Oct. 8 ruling, Sorokin wrote that a defense declaration "comprises a credible showing that Petrova was prosecuted due to her status as a Harvard-affiliated researcher and J-1 visa holder." He also pointed to the timing of the case, noting the complaint was filed "only two days before a hearing on a dispositive motion" in Petrova's habeas case in Vermont. A final status conference had been set for Nov. 30.

According to court records, Petrova, a Russian national, arrived at Logan from Paris on Feb. 16, 2025. The complaint, sworn by HSI Special Agent Brian Goldsworthy, charged her with smuggling goods into the United States, and a grand jury returned a three-count indictment in June 2025.

Sources: Government's Notice of Dismissal and Exhibits 1-3, U.S. v. Petrova, No. 1:25-cr-10272-LTS (D. Mass.), filed Nov. 3, 2026; Electronic Order and Order of Dismissal, Nov. 4, 2026; Memorandum and Order on Appeal of Magistrate Judge's Decision, Oct. 8, 2026; Criminal Complaint, May 12, 2025; Discovery order, April 1, 2026; court docket via CourtListener.