Romanian officials and acquaintances of Luminita Solcan, 36, said she was a highly intelligent woman who had plunged into paranoia and religious mania after the death of her father seven years ago.
Last Tuesday she stabbed Brother Roger Shultz, 90, the founder of an internationally celebrated monastery at Taizé in Burgundy, dedicated to the re-unification of the Christian church.
Ms Solcan was seized after slashing Brother Roger in the neck and back before a congregation of 2,500 young people from all over the world. She faces a charge of "assassination" or pre-meditated murder.
The public prosecutor for the Macon area of southern Burgundy, Jean-Louis Coste, said that she told investigators that she wanted to alert Brother Roger to the presence of "freemasons and wicked monks" in his 65-year-old ecumenical community. She admits pointing a knife at him but denies stabbing him.
In recent years, according to Romanian officials, Ms Solcan has made several attempts to join a convent, first in Romania, then in other countries. "We knew that she was under psychiatric surveillance and we could not accept her," said Fr Cornel Cadar, spokesman for the diocese of Iasi, Ms Solcan's home town. After being turned away by convents in France, Egypt and Switzerland, she approached members of the Taizé community.
Thousands of admirers amd well-wishers are converging on Taizé for Brother Roger's funeral on Tuesday. Although Roger Shultz was a Protestant, born in Switzerland, he will receive a Catholic funeral service in accordance with his own wishes.