Our guys:

Coalition officials announced Friday that they had arrested four Iraqi police officers in the ambush killings of two American occupation officials on a rural highway south of Baghdad earlier this week....

The apparent involvement of Iraqi police officers in the slayings is a blow to the credibility of a security service crucial to the coalition's plans for bringing stability to Iraq....

The Iraqi police, mostly drawn from former members of Saddam Hussein's police force, has taken on much of the front-line responsibilities for maintaining public order and deterring insurgent attacks as American troops shift to a supporting role....

[Coalition spokesman Dan] Senor described the coalition's screening procedures for police as "robust" but declined to go into greater detail.

"It is not perfect," Senor said. "Individuals slip through the cracks...."

--Chicago Tribune story via Kansas City Star