A scientist originally from Russia and a cancer researcher at Harvard University, who was charged with illegally bringing frog embryos into the United States, has been released after spending four months in federal detention as of Thursday. 

Kseniia Petrova, aged 30, was detained in February after returning from a holiday in France. During her trip, she received a shipment of very thin slices of frog embryos from a scientific facility for research purposes. When she arrived at Boston Logan International Airport, U.S. Customs and Border Protection officials questioned her about the items she was carrying. 

“I just want to thank everybody,” Petrova expressed on the steps of the federal courthouse in Boston after her release. “Many reached out to me, sending letters and offering support, which was immeasurable and without which I couldn’t have made it through.”

Kseniia Petrova, a Russian-born scientist and research associate at Harvard University, leaves the John Joseph Moakley United States Courthouse after she was released from U.S. federal custody while awaiting trial in a criminal case in Boston on June 12, 2025. (REUTERS/Reba Saldanha   )

Petrova’s colleagues have previously testified on her behalf, telling the court she is conducting valuable research that aids in searching for a cure for cancer. 

Greg Romanovsky, the immigration attorney representing Petrova, said his client has not “decided whether she wants to stay in the United States yet.” 

“She has offers from different countries around the world, countries that are eager to support the important research that she’s doing,” he said. “She’s weighing her options at the moment, and she’s very grateful to be out.” 

Romanovsky did not immediately respond to Fox News Digital’s request for comment. 

Under the conditions of her release, Petrova must report any contact with law enforcement – including ICE – to her supervising officer within 24 hours, according to court documents obtained by Fox News Digital. 

Petrova is scheduled to return to court next week for a probable cause hearing regarding the smuggling charge. 

The Associated Press contributed to this report.