The video, set to sweetly lilting religious hymns, is chilling. Islamic militants are shown knocking on the door of a Sunni police major in the dead of night in an Iraqi city. When he answers, they blindfold and cuff him. Then they carve off his head with a knife in his own bedroom.

The 61-minute video was recently posted online by the Islamic State of Iraq and the Levant, an al-Qaida splinter group of Sunni extremists. The intent was to terrorize Sunnis in Iraq’s army and police forces and deepen their already low morale…

Besides the scene of the beheading of the Sunni police major in Salaheddin province, the video includes footage of drive-by shootings of off-duty security personnel and the killings of captured army soldiers. In one scene, fighters masquerading as soldiers set up a checkpoint on a main highway, stopped cars and killed Shiites and security personnel by the side of the road.

In another horrifying scene, fighters abduct a Sahwa commander along with his two sons. They are forced to dig their own graves in the desert before their throats are slit.