A federal judge in Boston has dismissed every criminal charge against Kseniia Petrova, the Russian-born Harvard Medical School researcher who was charged with smuggling after she arrived at Logan Airport with frog embryos for her research. U.S. District Judge Leo Sorokin granted the government’s own motion to dismiss on Wednesday, November 4, 2026, without a hearing, the Associated Press reported.
The motion asked that the charges be dismissed with prejudice, which means they cannot be filed again, the Harvard Crimson reported. Petrova was never convicted of anything.
Why prosecutors dropped the case
U.S. Attorney Leah Foley filed the motion Tuesday night. “At this stage, the resource costs of continuing this prosecution outweigh the public interest in its resolution,” she wrote, according to the AP and the Crimson. She also wrote that Petrova’s “claims of vindictive and selective prosecution are meritless,” and the Crimson reported that the filing defended the original decision to charge her.
The motion pointed to an April ruling that granted the “defendant broad discovery in support of a selective prosecution” claim, the AP reported. Under that order, Foley wrote, the government would have had to turn over information on “any number of passenger encounters involving undeclared items that could be considered comparable,” along with Customs and Border Protection policies and procedures.
Why that April discovery order mattered
A defendant who claims she was singled out for prosecution usually cannot get far enough to see the government’s files. In United States v. Armstrong, 517 U.S. 456 (1996), which we verified and read on CourtListener, the Supreme Court said the standard for a selective-prosecution claim “is a demanding one,” and that the showing needed just to obtain discovery “should itself be a significant barrier to the litigation of insubstantial claims.” Prosecutors get a “presumption of regularity,” the Court said.
Petrova’s lawyers argued that the government filed criminal charges only after it looked like she would win her immigration case, and that it is rare for anyone to be charged criminally for failing to declare items like hers, the AP reported. In April, a federal judge allowed her request for government records on similar cases, the Crimson reported. Rather than produce those records, the government asked to end the case.
How a prosecutor drops a federal case
Federal Rule of Criminal Procedure 48(a), which we read at Cornell’s Legal Information Institute, says the government “may, with leave of court, dismiss an indictment, information, or complaint.” The judge has to approve it. Judge Sorokin did.
How the case began
- February 2025. Returning from France, where she had obtained frog embryo samples from a lab, Petrova was questioned at a customs checkpoint at Logan, and officers canceled her visa, according to the AP and the Crimson. The Department of Homeland Security said she was “lawfully detained after lying to federal officers,” the AP reported. She has denied lying, the Crimson reported.
- Four months in ICE custody. She was held in Vermont and Louisiana before a judge ordered her release in May 2025, according to the Crimson.
- The charges. Prosecutors first charged her with smuggling. A grand jury later indicted her on one count of smuggling goods into the United States, one count of concealment of a material fact and one count of false statement, the AP reported.
- April 2026. A federal judge ruled that a customs officer improperly canceled her visa, the AP reported, and the case “began to fall apart.”
What her lawyers said
“The DOJ never should have brought this highly unusual ‘smuggling’ prosecution against Kseniia Petrova, a talented scientist at Harvard,” her attorney Daniel Marx said in a statement reported by the AP. Another of her lawyers, William Fick, said, “we are relieved that this chapter of her terrible ordeal will soon be over,” the Crimson reported.
The criminal case is over. Her immigration case is separate, and we could not find a current report on its status.
Frequently asked questions
Were the charges against Kseniia Petrova dropped?
Yes. Judge Leo Sorokin granted the government’s motion to dismiss all charges on November 4, 2026, the AP reported.
Can she be charged again?
No, if the dismissal is with prejudice, as prosecutors requested, according to the Harvard Crimson.
Did the government admit it was wrong?
No. The U.S. Attorney’s motion called her vindictive and selective prosecution claims “meritless” and cited the cost of continuing the case.
What is selective prosecution?
A claim that the government charged someone for an unconstitutional reason while not charging others in the same situation. Under United States v. Armstrong, it is hard to prove and hard even to get discovery on.
Sources: Associated Press, November 4, 2026, as published by WBUR, Boston.com and CNN; The Harvard Crimson, November 4, 2026. Federal Rule of Criminal Procedure 48, read at Cornell’s Legal Information Institute. United States v. Armstrong, 517 U.S. 456 (1996), verified and read on CourtListener. We did not obtain the court docket. General information, not legal advice.