Iraqi Police being trained by Americans in proper treatment of prisoners ...

BBC NEWS | Middle East | Iraq police accused of torture

The return to torture and killing by the security forces is another embarrassment for the American and British governments, which have partly justified the invasion of Iraq on the grounds of ending the kind of abuses committed by Saddam Hussein's regime.
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What is also a major concern is that the minority Sunni Muslim community who used to control Iraq believe they are now being deliberately targeted by the Shia-dominated police force.
The insurgency is led by militant Sunnis whereas the government is now led by the majority Shia.
In their brutal campaign of violence, the insurgents have focused their attacks on Shia and members of the Iraqi security forces in order to provoke sectarian conflict.
If the security forces respond with torture and extra-judicial killings, it could lead to exactly what the insurgents want - full-blown sectarian war.