ABC News is reporting that military officials have completed their investigation and concluded that U.S. forces followed the rules of engagement in Ishaqi in March. While they did indeed kill the 11 civilians noted, there is no evidence of a "massacre".
I am inclined to accept this, as it jibes with Juan Cole's argument that the "long-range bullet wounds may indicate that they [U.S. troops] went in, guns blazing, before they realized who they were killing." While I do not trust the MSM on such things, I do trust Mr. Cole.
The troops were supposed to be after, and apparently apprehended, a suspected al-Qaeda suspect. The rest were "collateral damage".