Amina Tyler, 19, posted a photo of herself without a top on and with the words "My body belongs to me" written in Arabic across her chest. The woman is a native of Tunisia.
Tyler is known to be a FEMEN activist. Reports indicate she might not have been in Tunisia when she posted the photos onto her Facebook.
Her parents have since taken her to a psychiatric hospital in Tunis.
Media in Tunisia claim that if Amina did post the photo in her home country, she may be punished for two years in prison and given a fine between £40 and £400.
But many religious leaders don't care if it was taken in the country or not, and are ready to take the law into their own hands.
Salafi preacher Adel Almi said: "According to God's law, she deserves 80 to 100 lashes, but what she committed is worth much more than that. She deserves to be stoned to death and she must be quarantined because what she did is an epidemic."
"She is like someone suffering from a serious and contagious illness and she must be secluded and treated."
It didn't take long for FEMEN to fight back against the preacher's comment, saying that April 4 "will mark the beginning of a new, genuine Arab Spring, after which true freedom, freedom without mullahs and caliphs, will come to Tunisia."
They ended their statement with, "Our tits are deadlier than your stones!"
The group organized a petition and an international day of action for April 4. More than 10,000 people have signed the petition calling for those who threatened Amina to be prosecuted.
A Human Rights Watch spokesman said, "The comments of the Tunisian preacher Adel Almi saying that Amina Tyler should be stoned to death could put her at serious risk of being harmed."
"The Tunisian state should react at the very least by condemning these words and protecting her from physical assault, and investigate if the crime of inciting violence has taken place."