The extremist Islamic group known as the Islamic State - also called ISIS or ISIL - and groups connected with it - are believed to have killed thousands of civilians in Iraq and Syria, as well as having executed hundreds of Syrian and Iraqi security forces. To a lay person, this would seem like a clear-cut case of genocide. But is it genocide under international law? And if so, what can or should be done about it? VOA's Sharon Behn takes a look at those questions.