A masked, black-clad militant, who has been identified by the Washington Post newspaper as a Briton named Mohammed Emwazi, stands next to a man purported to be Steven Sotloff in this still image from a video obtained from SITE Intel Group website February 26, 2015. Photo courtesy of REUTERS
*Editors: This photo may not be republished.
(RNS) Mohammed Emwazi, who is in his mid-20s, is believed to be a Kuwaiti-born British man from west London. The BBC said he was known to British security services, who chose not to disclose his name for operational reasons.