Peter Kassig was an Iraq War veteran who went to Syria to volunteer at hospitals. In a profile aired by CNN in 2012, Kassig said he's an idealist who believes in hopeless causes.
Islamic State militants have stepped up attacks on Kobani, which lies along the Turkey-Syria border and has been encircled by the extremists for weeks.
After several young people left to join ISIS, leaders are considering which approach to take with marginalized youth. Boston's experience with the marathon bombing suspects may be instructive.
Activists say militants are holding hundreds, perhaps thousands of Yazidi women in northern Iraq. The women make contact through secret phones; some men have been killed or beaten trying to save them.
The High Commissioner for Human Rights says mass executions, forcing women and girls into sex slavery and the use of child soldiers may constitute war crimes and crimes against humanity.
The former homeland security secretary and Arizona governor also talks about security improvements since the Sept. 11 attacks and the frustrations and potential solutions to the immigration debate.
In an interview with 60 Minutes the president, citing the director of national intelligence, acknowledged that U.S. intelligence overestimated the ability of the Iraqi army to fight the group.