The Islamic State militant group released a video Tuesday purporting to show the beheading of a second US hostage, Steven Sotloff, whose death was threatened after the murder of American journalist James Foley, if the US continued to attack IS. The black-clad knife-wielder said that as long as US missiles “continue to strike our people, our knife will continue to strike the necks of your people." The Islamists now threaten that a British hostage, David Haines, will be next, unless the US backs off from its attacks.