AlterNet: Hurricane Katrina: Left to Die in a New Orleans Prison: "We're certainly not saying that those people drowned in the facility, but there are credible reports from inmates of being left in that facility in locked cells. And so we'd like to know from the Orleans Sheriff and from the Department of Corrections what happened to those 517 people."

...

"It's clear to us from talking to inmates in that facility -- and other lawyers in Louisiana have talked to well over 1,000 prisoners at this point -- that by Monday when the storm hit, guards were no longer in the facility. The inmates were left to fend for themselves during the storm.

The most disturbing thing is that the water began to rise in many of the buildings. Some inmates tell us that the water had come up to their chest level, and they were still in locked cells. Some other inmates helped them get out of those cells and escape the floodwaters to higher levels of the facility. They were also left there without any food or water for up to four days. There was no air circulation, and the toilets had started to back up. So the stench was unbearable for these prisoners. "

Emphasis Mine.

(Via AlterNet.)