Scientist who brought frog embryos to Boston for cancer research is cleared of smuggling charges

Leah Willingham/AP/File

US prosecutors have dropped all criminal charges against a Russian scientist who was tossed into an immigration jail last year after she landed at a Boston airport with frog embryos intended for her cancer research at Harvard Medical School.

Kseniia Petrova, 31, spent four months in detention following her arrest in early 2025 as she returned from a vacation in France, where she had stopped at a lab specializing in splicing superfine sections of frog embryos and obtained a package of samples for research.

She was questioned about the samples while passing through a customs checkpoint at Logan International Airport, then later charged with smuggling .

A federal judge on Wednesday granted a request by prosecutors to dismiss those charges as well as counts alleging that she’d concealed facts and made false statements to government officials.

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.

The case began to fall apart in April, after a federal judge ruled a customs officer improperly canceled Petrova’s visa over the incident. Petrova had feared being deported to Russia and imprisoned there.

Her lawyers had also argued that the criminal prosecution was vindictive, saying the government filed criminal charges only after it looked like she would win her immigration case. They also argued that it was rare for anyone to be charged criminally for what Petrova did.

On Tuesday night, US Attorney Leah Foley filed a motion to dismiss the charges “based on developments in this case and an assessment of the office’s priorities and resources.”

“At this stage, the resource costs of continuing this prosecution outweigh the public interest in its resolution,” she wrote, adding that the “defendant’s claims of vindictive and selective prosecution are meritless.”

US District Judge Leo Sorokin, who was nominated by former President Barack Obama, dismissed the charges Wednesday without a hearing.

“The DOJ never should have brought this highly unusual ‘smuggling’ prosecution against Kseniia Petrova, a talented scientist at Harvard,” one of Petrova’s attorneys, Daniel Marx, said in a statement. “Ms. Petrova only sought to advance medical research into aging that could benefit everyone, and her handling of scientific samples — inert, non-living, non-toxic, frog embryos — never posed any danger to anyone.”

Earlier this year, the Department of Homeland Security defended Petrova’s detention, saying she had lied to federal officers about the frog embryos.

In a court filing asking the judge to dismiss the case, Foley cited an April court ruling that would have allowed Petrova’s lawyers to get broad access to government documents as part of her defense that she was being prosecuted selectively.

“The government must supply the defendant with information pertaining to any number of passenger encounters involving undeclared items that could be considered comparable, without regard for the manner in which those items were carried, the presence or absence of planning, or the strength of the evidence of a passenger’s fraudulent intent,” Foley wrote.

莉亚·威林厄姆/美联社/档案照片

美国检察官撤销了对一名俄罗斯科学家的所有刑事指控。该科学家去年抵达波士顿机场时携带了青蛙胚胎，原本计划用于她在哈佛医学院的癌症研究，随后被关进了移民监狱。

31 岁的克谢尼娅·彼得罗娃 (Kseniia Petrova) 在 2025 年初被捕，当时她刚从法国度假回来。她在法国期间曾到一家专门拼接青蛙胚胎超细切片的实验室，并获得了一包用于研究的样本。她在法国被捕后被拘留了四个月。

她在洛根国际机场海关检查站接受讯问时被问及这些样品，随后被指控走私。

周三，一名联邦法官批准了检察官的请求，驳回了这些指控，以及指控她隐瞒事实和向政府官员作虚假陈述的指控。

佩特罗娃在接受美联社采访时表示，她没有意识到这些物品需要申报，也没有试图偷偷将任何东西带入该国。

这起案件在四月份开始出现转机，当时一名联邦法官裁定，一名海关官员因该事件不当取消了佩特罗娃的签证。佩特罗娃一直担心会被遣返回俄罗斯并在那里入狱。

她的律师还辩称，刑事诉讼是出于报复，称政府是在她移民案胜诉在望之后才提起刑事诉讼的。他们还指出，像佩特罗娃这样的行为被刑事起诉实属罕见。

周二晚上，美国检察官莉亚·弗利提交了一份动议，要求“根据本案的进展以及对检察官办公室的优先事项和资源的评估”撤销指控。

她写道：“现阶段，继续进行此案的资源成本超过了公众对此案得到解决的利益”，并补充说，“被告关于进行报复和选择性起诉的说法毫无根据”。

由前总统巴拉克·奥巴马提名的美国地区法官利奥·索罗金周三驳回了这些指控，没有举行听证会。

“司法部根本不应该对哈佛大学才华横溢的科学家克谢尼娅·彼得罗娃提起如此非同寻常的‘走私’诉讼，”彼得罗娃的律师之一丹尼尔·马克思在一份声明中表示。“彼得罗娃女士只是想推进衰老医学研究，造福全人类，而她处理的科学样本——惰性、非生物、无毒的青蛙胚胎——从未对任何人构成任何危险。”

今年早些时候，国土安全部为拘留佩特罗娃辩护，称她就青蛙胚胎一事向联邦官员撒谎。

在要求法官驳回此案的法庭文件中，弗利引用了四月份的一项法院裁决，该裁决允许佩特罗娃的律师广泛查阅政府文件，作为她辩称自己受到选择性起诉的一部分。

“政府必须向被告提供与任何数量的乘客携带未申报物品有关的、可被视为可比的事件的信息，而不管这些物品的携带方式、是否有计划，或者乘客欺诈意图的证据强度如何，”福莱写道。