BOSTON — The U.S. Attorney’s Office for the District of Massachusetts announced today that Kseniia Petrova, a 31-year-old Russian national and research associate at Harvard Medical School, has been charged with smuggling biological materials into the United States.
Petrova was arrested on February 16, 2025, at Boston’s Logan International Airport after customs officials discovered undeclared frog embryos and embryonic samples in her luggage upon her return from Paris.
Following her arrest, Petrova was initially taken into immigration custody and held at a detention facility in Vermont for about a week before she was transferred to the Richwood Correctional Center in Monroe, Louisiana, where she has remained since. On May 14, 2025, she was formally charged by criminal complaint with one count of smuggling goods into the United States, according to the U.S. Attorney’s Office for the District of Massachusetts.
According to charging documents, a law enforcement canine alerted agents to Petrova’s duffel bag, which was found to contain a foam box with clawed frog embryos in microcentrifuge tubes, as well as embryonic samples embedded in paraffin and mounted on dyed slides. All biological products require a permit for entry and require the individual transporting them to make a declaration to Customs & Border Protection at the port of first arrival, according to the U.S. Attorney’s Office for the District of Massachusetts.
Prosecutors allege that when she was first approached by law enforcement, Petrova denied carrying any biological materials but later admitted to possessing the samples. Text messages retrieved from her phone indicated that colleagues had warned her about the need to declare such materials. In one exchange, a colleague advised, “if you bring samples or antibody back, make sure you get the permission etc. Like that link I sent to leon-/group chat about frog embryos because TSA went through my bags at customs in Boston;” and “What is your plan to pass the American Customs with samples? This is the most delicate place of the trajectory.”
In another text message conversation with an individual identified as her principal investigator, Petrova was asked how she planned to get through customs with the biological samples, to which she replied: “No plan yet. I won’t be able to swallow them.”
Following the discovery, Customs and Border Protection (CBP) revoked her J-1 research visa, and she was taken into immigration custody.
Petrova is a bioinformatics researcher who joined Harvard Medical School’s Department of Systems Biology in 2023, where she worked in the prestigious Kirschner Lab. Her research focuses on cellular aging and regeneration, utilizing Xenopus laevis (African clawed frog) embryos to study early developmental stages.
Her attorney, Gregory Romanovsky, criticized the government’s handling of the case, stating that the visa revocation and subsequent detention were excessive responses to a customs violation that typically results in a fine. He argues that the smuggling charge, filed in May 2025, was strategically timed to justify her continued detention and potential deportation.
Petrova fears returning to Russia due to her political activism and previous arrest in Moscow in February 2022 for protesting the war in Ukraine. She has expressed concerns about facing imprisonment or worse if deported.
If convicted, Petrova faces up to 20 years in prison, up to five years of supervised release, and a fine of up to $250,000.
Petrova remains in detention as she awaits a transfer to Massachusetts for federal court proceedings.
