More questions about the official Najaf story

Zeyad at his Healing Iraq website has new information on circumstances surrounding the Najaf fighting, including this:

Another story that is surfacing on several Iraqi message boards goes like this: A mourning procession of 200 pilgrims from the Hawatim tribe, which inhabits the area between Najaf and Diwaniya, arrived at the Zarga area at 6 a.m. Sunday. Hajj Sa’ad Nayif Al-Hatemi and his wife were accompanying the procession in their 1982 Super Toyota sedan because they could not walk. They reached an Iraqi Army checkpoint, which suddenly opened fire against the vehicle, killing Hajj Al-Hatemi, his wife and his driver Jabir Ridha Al-Hatemi. The Hawatim tribesmen in the procession, which was fully armed to protect itself in its journey at night, attacked the checkpoint to avenge their slain chief. Members of the Khaza’il tribe, who live in the area, attempted to interfere to stop the fire exchange. About 20 tribesmen were killed. The checkpoint called the Iraqi army and police command calling for backup, saying it was under fire from Al-Qaeda groups and that they have advanced weapons. Minutes later, reinforcements arrived and the tribesmen were surrounded in the orchards and were sustaining heavy fire from all directions. They tried to shout out to the attacking security forces to cease fire but with no success. Suddenly, American helicopters arrived and they dropped fliers saying, “To the terrorists, Surrender before we bomb the area.” The tribesmen continued to fire in all directions and in the air, but they said they didn’t know if the helicopter crash was a result of their fire or friendly fire from the attackers. By 4 a.m., over 120 tribesmen as well as residents of the area had been killed in the U.S. aerial bombardment.

Note that this describes events in the Zarka (or Zarga I guess is better) area just outside Najaf. This is where the messianic followers of Ahmad al-Hassan had their colony, according to Azzaman and others, but according to this account the trigger-event had nothing to do with them, rather with a group from the Hawatim tribe, passing through the area, or trying to, in order to participate in the Ashura processions in Najaf. Trigger-happy persons initiated an exchange of fire at an Iraqi army checkpoint, which was then joined in by another tribe, the Khazail, which lives in the area. American helicopters appeared, dropping leaflets warning the "terrorists" they were about to bomb the area.

Zeyad tells us that both the Hawatim and the Khazail tribes are non-SCIRI, non-Dawa Shiite. He writes:

Both the Hawatim and Khaza’il tribe are anti-SCIRI and anti-Da’wa. Last July, they threatened to kill any of their members who join the Mahdi Army or the Badr Organization. SCIRI, on the other hand, accuses the tribes of being Ba’athists and Saddam loyalists.

This provides an interesting explanation of the Azzaman statement this morning, to the effect that the Ahmad al-Hasan's messianic group had settled in an area that was not submissive to either the SCIRI or the Dawa parties. Thus there were three groups involved, all of them no doubt regarded by the SCIRI/Dawa Najaf authorities as enemies: A tribe passing through and challenged at a checkpoint, a resident tribe, and the messianic group itself. And since SCIRI/Dawa are the core of the Baghdad government, it is easy to imagine all of these groups being targets of the central government forces too.

Which only adds to the urgency of the question: Where is the actual evidence that any of these groups posed any actual danger, apart from self-serving statements by the Najaf and Baghdad authorities. Or was this more like a massacre, premeditated or accidental?