Óscar Arias Sánchez, a Nobel Peace Prize winner and former president of Costa Rica, has been accused of sexually assaulting a psychiatrist and antinuclear activist four years ago, The New York Times reports. Alexandra Arce von Herold, a nuclear disarmament activist who often worked with the former president, said she was at Arias’ home in 2014 for work when he allegedly came up behind her, touched her breasts, and shoved his hands up her skirt, penetrating her with his fingers. Arce filed a criminal complaint with federal prosecutors on Monday and gave a statement under penalty of perjury asking them to charge Arias with sexual assault. Arias won the Nobel Peace Prize in 1987 for brokering a plan to end civil wars in Central America, and remains one of the most powerful figures in Costa Rica. Arce told a number of people about the alleged assault, including colleagues and her brother, who said that for weeks afterward, “it was like she had PTSD. She didn’t feel safe.”