Prior to Katrina, New Orleans had a murder rate something like eight times the national average. So a 30% jump in San Antonio is not surprising.
For once, I am actually thankful for the local gangs here in Houston, because they largely have run the New Orleans animals out of town. For a while, the evacuees were running rampant slaughtering locals, then all of a sudden you noticed it was the evacuees themselves getting killed, then next thing you know the murder rates go back to (relatively) normal in Houston, and New Orleans goes from freakishly low crime to making Baghdad look like Geneva.