A Russian scientist, Darya Shipilova, dies after developing a rapidly progressing illness while working at the Irkutsk Anti-Plague Research Institute in Siberia, according to reports. Her mother, Svetlana Shipilova, publicly disputes an official explanation and says authorities “simply let my daughter die.” She also challenges earlier claims that Shipilova was infected after accidentally breaking a test tube containing live biological material.

Authorities say her death is linked to pneumonia of unknown origin and that testing found no evidence connecting her illness to dangerous laboratory pathogens, Russia’s public health watchdog Rospotrebnadzor reports. After her death, officials reportedly quarantine about 200 people and put laboratory employees under observation.

International attention includes statements that U.S. officials are seeking additional information from Moscow. The Washington Post reports U.S. coordination involving federal agencies, while other outlets say President Donald Trump has indicated he will raise the issue with Russian President Vladimir Putin. The differing accounts centre on whether the death was accidental and lab-related or instead a result of authorities’ actions, as alleged by the mother.