ISIS on Tuesday released a video purporting to show the execution of journalist Steven Sotloff, and it warned the world to end "this evil alliance of America against the Islamic State." The White House could not immediately confirm the authenticity of the video, but spokesman Josh Earnest said intelligence officials were working to verify it.
Last month, ISIS released a video showing the beheading of journalist James Foley. That video ended with Foley's executioner holding Sotloff and threatening to kill him as well unless the U.S. backed down.