One of the most prominent figures in the peaceful protest movement that swept Syria early in the country's uprising was reported missing Tuesday from a rebel-controlled suburb of Damascus, prompting suspicions she is among the scores of civilian activists and journalists who have been detained by Islamist extremists in recent months.

Razan Zaitouneh, 36, a human rights lawyer, disappeared from her apartment with her husband and two other activists overnight Monday after threats received from Islamist groups, according to the opposition group of which she was a founder, the Local Coordination Committees.

The apparent targeting of a woman so closely associated with the peaceful origins of the revolt ricocheted through the already demoralized activist community, drawing condemnations on Twitter and Facebook, as well as soul-searching.