US District Judge Leo Sorokin on Wednesday granted prosecutors' request to dismiss all charges against Kseniia Petrova. He did not hold a hearing, The Guardian reported. Petrova, 31, is a Russian scientist who brought frog embryos into the US for cancer research at Harvard Medical School.
Petrova was arrested in March 2025 at Boston's Logan International Airport. She was returning from a holiday in France, where she had visited a laboratory that cuts extremely thin sections of frog embryos. There she picked up a package of samples for her research in the US. Customs officials questioned her about the samples. She was later charged with smuggling, concealing facts and making false statements to government officials.
The case began to unravel when a federal judge ruled that a customs officer had improperly cancelled her visa. Petrova had feared deportation to Russia, where she could face prison. She had fled Russia after being arrested for protesting against the invasion of Ukraine. A judge ordered her release in May 2025.
On Tuesday night, US Attorney Leah Foley filed a motion to drop the case. She cited "developments in this case and an assessment of the office's priorities and resources". Foley wrote that the cost of continuing the prosecution outweighed the public interest in resolving it. She also said Petrova's claims of vindictive and selective prosecution were meritless.
Petrova's lawyers had argued that the charges were vindictive. They said prosecutors filed them only once it looked like she would win her immigration case. They also said criminal cases over conduct like hers were rare. After the dismissal, her attorney Daniel Marx said the Department of Justice should never have brought the case. He called it a highly unusual smuggling prosecution. He said the samples were inert, non-living and non-toxic frog embryos that never posed a danger to anyone.
The Department of Homeland Security has continued to defend the arrest. It maintains that Petrova lied to federal officers about the embryos. Her colleagues at Harvard described her research talents as "spectacular".
According to The Guardian, the case was one of many high-profile immigration arrests involving academics in the early months after President Donald Trump returned to the White House. He had promised a crackdown on immigration. Petrova is among numerous noncitizen academics arrested or threatened with deportation by his administration.