Hi there Amy,
Trulia has a built in crime map which you can use to see how crime varies block to block, neighborhood to neighborhood.
Here is our Crime Map for the 77099 zip code you were asking about: http://www.trulia.com/real_estate/77099-Houston/crime/
But you can also see this at a finer level, by going back to the property page, scrolling down to the Local Info section, and clicking the "Crime" tab above the map.
Good luck with your search!
Community Manager, Trulia Voices