Why Has AP Revised November 28 'Burning Six' Story?

Curt at Flopping Aces notes that the Associated Press has quietly changed the copy of their November 28 response to questions about the "burning six" story. And the Google cached version apparently has been changed, as well.

The AP angrily rejected criticism of its story about six Sunni men being dragged from prayer and burned alive after CENTCOM, the Iraqi Ministry of the Interior, and bloggers questioned the identity of "police captain Jamil Hussein," their chief source for the story. CENTCOM and the MOI say that no such person is listed as a police captain. Hussein had previously been quoted by the AP in more than sixty stories over the past two years.

After Confederate Yankee noticed that the page briefly went down, an unacknowledged paragraph rewrite appeared:

AP reporters who have been working in Iraq throughout the conflict learned of the mosque incident through witnesses and later corroborated it with police.

USA Today still has the original copy posted:

AP reporters who have been working in Iraq throughout the conflict learned of the mosque incident through witnesses and neighborhood residents and corroborated it with a named police spokesmen and also through hospital and morgue workers.

The "neighbors" and "hospital and morgue workers" copy has been expunged.

Why would the Associated Press try to change the record on a controversial story, especially one in which the AP's sourcing has come into question?

Update: Allahpundit at HotAir thinks that the quotes are from two different documents, but wonders why the supporting witnesses were left out of the later document. I'm not convinced that there were two documents. The copy is just too similar.