Another scene in a recent video meant to intimidate Sunnis into deserting or surrendering show a police officer being beheaded in his own bedroom.

CAIRO (AP) – 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.

That fear is one factor behind the stunning collapse of Iraqi security forces when fighters led by the Islamic State overran the cities of Mosul and Tikrit this week, sweeping over a swath of Sunni-majority territory. In most cases, police and soldiers simply ran, sometimes shedding their uniforms, and abandoned arsenals of heavy weapons.

Even after the United States spent billions of dollars training the armed forces during its 2003-2011 military presence in Iraq, the 1 million-member army and police remain riven by sectarian discontents, corruption and a lack of professionalism.

Many Sunnis in the armed forces are unprepared to die fighting on behalf of Prime Minister Nouri al-Maliki’s Shiite-led government, which many in their minority community accuse of sharp bias against them. The Islamic State has exploited this by touting itself as the Sunnis’ champion against Shiites. […]

The harrowing video put out 10 days ago by Islamic State’s media arm, Al-Furqan, underscores the threats to Sunnis in pro-government forces.

Speaking on condition of anonymity for fear of reprisals, Iraqis contacted in Anbar and the provinces where Mosul and Tikrit are located said the video was widely seen. They spoke of people they knew personally who deserted the military after watching the footage of the summary beheading.

One resident of Fallujah, identifying himself only by his nickname Abu Ali, said the video brought home the Islamic State’s brutality. But he said morale is already low among troops because of almost daily attacks by jihadis on army positions. “The strikes by fighters in the streets had more effect than the video,” he said.

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.

“I advise whoever is with the Sahwa to repent and quit,” the commander says to the camera. “Here I am digging my grave with my own hands. … They can get to anyone.”