Oksana Shachko, one of the three women who founded Ukranian feminist organization Femen, was found dead in her Paris apartment on Monday.
“RIP. The most fearless and vulnerable Oksana Shachko has left us. We mourn together with her relatives and friends,” the organization wrote in an announcement published to its blog on Tuesday.
The group added that it is waiting for the “official version from the police” before providing more information. The Ukranian embassy confirmed Shachko’s death to a Russian television network.
French authorities have yet to release an official cause of death, but multiple outlets, including Agence France-Presse, reported that the 31-year-old activist was found with a suicide note next to her body.
“It is with great regret and deep pain that I must confirm the death of Oksana,” Femen co-founder Inna Shevchenko told AFP.
Another of the three co-founders of Femen, Anna Hustol, posted the official announcement to her Facebook page with a photo of Shachko.
Shachko exiled to France in 2013 and left Femen. Since then, she had been working as an artist.
During the five years she was in Femen, Shachko was arrested dozens of times, interrogated, allegedly abused by police and spent almost a year in jail. She was also one of the members who was allegedly kidnapped in Belarus in 2011 after protesting the Belarusian president Alexander Lukashenko during a topless rally. Shachko and other members said they were forced to strip naked in the woods, were beaten, had oil poured on them and were threatened to be set on fire.
“She must have committed suicide at the last drop of her suffering ― she had experience tons; I am not surprised she has done it, her entire life has never been easy, she had layer upon layer of pain,” photographer Dmitry Kostyukov, husband of Femen co-founder Shevchenko, told The Daily Beast.
Femen, known for its topless protests, was founded in Kiev, Ukraine, in 2008. Shachko, Shevchenko and Hustol were only 17 when they founded the group with the slogan, “I came, I stripped, I won.” According to the organization’s website, Femen protesters use “sextremism” in order to execute “complete victory over the patriarchy.”
“Female nudity, free of patriarchal system, is a grave-digger of the system, militant manifesto and sacral symbol of women’s liberation,” the website reads.
The international feminist movement often protested sexism, homophobia, religious institutions such as the Catholic church and the politics of President Donald Trump.
If you or someone you know needs help, call 1-800-273-8255 for the National Suicide Prevention Lifeline. You can also text HOME to 741-741 for free, 24-hour support from the Crisis Text Line. Outside of the U.S., please visit the International Association for Suicide Prevention for a database of resources.
This article originally appeared on HuffPost.