US Secretary of State John Kerry discusses the killing of American journalist Steven Sotloff, describing his murder at the hands of Islamic State (Isis) as 'unfathomable brutality'. Kerry reiterated that the U.S. will hold the islamic jihadist who committed the murder accountable. Isis released a video on Tuesday that shows the beheading of a second American hostage, following James Foley's murder In August. The video also included a threat to murder a British hostage next