Police presume the death was suicide but are investigating the exact circumstances surrounding the incident.
According to an official from the Jogye Order, the country’s largest Buddhist denomination, Lee left a suicide note at the spot saying she was following Venerable Munsu’s will.
Venerable Munsu, 47, set himself on fire on a river bank near the Jibosa temple in May 2010, after demanding President Lee Myung-bak’s government “stop the river project immediately and try its best to serve poor people, not the rich.”
The Buddhist official said Lee was a former novice nun and devotee of the dead monk.
Father Hugo Park Jung-woo, secretary of the Korean bishops’ Committee for Justice and Peace, expressed his sadness at her death, saying she was another victim of the government’s disregard for ordinary people and nature.
The river project entails dredging and damming sections of the country’s major waterways.
The government claims it is to prevent flooding and pollution, but many opponents including religious people and environmentalists say it will have the opposite effect.