The Islamic State group has released another video, this time said to show the beheading of American journalist Steven Sotloff.
The 31-year-old had been filmed in another video released two weeks ago in which journalist James Foley is said to have been killed.
The latest atrocity has been condemned by world leaders as inhuman, barbaric and pure evil. The video shows a third captive, said to be a British hostage, whom Islamic State has also threatened to kill.
Titled A Second Message to America, an Islamic State fighter tells the camera that the killing is in retaliation for US air strikes on Iraq. The US is consulting NATO allies on possible further action against the IS.
But does the answer lie closer to home?
In the so-called surge in Iraq in 2007 and 2008, US troops worked with Sunni tribes and fighters against al-Qaeda. The grass roots Awakening Councils helped turn the tide against al-Qaeda's insurgency.
But following years of marginalisation, can Sunni groups be encouraged to take on al-Qaeda’s incarnation?
Presenter: Hazem Sika
Aymenn Jawad al-Tamimi - fellow at the Middle East Forum
Ahmed Rushdi - director of the House of Iraqi Expertise Foundation
Martin Reardon - vice president of the Soufan Group - an intelligence and security company