Court closes criminal case against Russian scientist Ksenia Petrova, who was accused of illegally importing frog embryos into the United States A federal judge dismissed a criminal case against Russian scientist Ksenia Petrova, who worked at Harvard Medical School. Petrova was charged with smuggling for failing to declare the frog embryos she carried in her suitcase when she returned to the United States in February. She brought samples at the request of her scientific supervisor. The day before, the US Department of Justice submitted a petition to the court requesting to dismiss the case. A district judge in Massachusetts ruled accordingly.