Yeah, it looks like we're starting to get some real information from the media and not just partisans hurling insults. Here's a pretty good story I found in the times about the disaster:

http://www.nytimes.com/2005/09/11/national/nationalspecial/11response.html?pagewanted=1

This excerpt about the violence in the convention center starts as the last paragraph on page 4 of that story:

While those entering the Superdome had been searched for weapons, there was no time to take similar precautions at the convention center, which took in a volatile mix of poor residents, well-to-do hotel guests and hospital workers and patients. Gunfire became so routine that large SWAT teams had to storm the place nearly every night.

Capt. Winn said armed groups of 15 to 25 men terrorized the others, stealing cash and jewelry. He said policemen patrolling the center told him that a number of women had been dragged off by groups of men and gang-raped - and that murders were occurring.
"We had a situation where the lambs were trapped with the lions," Mr. Compass said. "And we essentially had to become the lion tamers."

Capt. Winn said the armed groups even sealed the police out of two of the center's six halls, forcing the SWAT team to retake the territory.

But the police were at a disadvantage: they could not fire into the crowds in the dimly lit facility. So after they saw muzzle flashes, they would rush toward them, searching with flashlights for anyone with a gun.

Meanwhile, those nearby "would be running for their lives," Capt. Winn said. "Or they would lie down on the ground in the fetal position."

And when the SWAT team caught some of the culprits, there was not much it could do. The jails were also flooded, and no temporary holding cells had been set up yet. "We'd take them into another hall and hope they didn't make it back," Capt. Winn said.

One night, Capt. Winn said, the police department even came close to abandoning the convention halls - and giving up on the 15,000 there. He said a captain in charge of the regular police was preparing to evacuate the regular police officers by helicopter when 100 guardsmen rushed over to help restore order.