Post-Katrina Abuse of Power

Before this unit, I'd heard about the numerous failures of FEMA and the local government to respond adequately to the devastation wrought by Katrina, but I had always thought of this as a series of escalating innocent-enough mistakes with terrible consequences. Perhaps unbelievably, it wasn't until I saw Trouble the Water and heard Scott Roberts' testimony of being threatened when he and his family approached the Army base (and the officials' subsequent denial of the veracity of his claim) that I began to realize that some of the injustices committed against the people of New Orleans following the hurricane may have been intentional and/or malicious.
http://www.nytimes.com/2011/08/06/us/06danziger.html?pagewanted=1&ref=hurricanekatrina
^ This article seems particularly relevant in the wake of the highly publicized Trayvon Martin case, in which a young, unarmed African American male was shot and killed because he was deemed "threatening". Obviously, the differences between the cases abound - Martin's killer was a civilian, for one thing, and white, while the officers culpable here were a mixed-race group - but the knee-jerk impulse to shoot potential or suspected black offenders on-sight is one that seems to pervade among authorities (or those that think of themselves as such) in our country.
At any rate, this article serves to solidify my new understanding of the state of affairs in New Orleans immediately following the storm. I used to ascribe to the old "citizenry run rampant" narrative, but after witnessing in Trouble the Water and A.D. a largely positive camaraderie among the affected, as well as how many of the so-called "thugs" responsible for raids and other widely publicized legal transgressions actually did a better job of caring for people than did the authorities (as is the case in A.D.'s Denise storyline), I have a different view of who may have been to blame for contributing to the disaster in certain situations; as this article states, "it has become apparent that some of the bloodshed and chaos was brought about by members of the long-troubled police department". While I don't know much about the NOPD, the "long-troubled" descriptor may specify why, on the Treme Wikipedia page, Terry Colson is listed as "an honest cop" (I sort of figured all cops were presumed honest). (http://en.wikipedia.org/wiki/Treme_(TV_series) )
The cover-up element of this case is particularly disturbing, and makes me wonder about the dynamite rumor brought up in A.D. and refuted by Treme's Creighton Bernette. I'm pretty sure that one's been debunked in the years since, but perhaps there have been other Katrina-related governmental cover-ups that haven't even been brought to light yet.