David has given you a good resource in the police department. His is right that realtors are not permitted by the US government of detailing crime ridden areas even if the areas are unsafe for children. We can give buyers resources and general advice on how to stay safe. You might ask the police about the places where gangs are currently meeting.
Here is another resource: www.familywatchdog.us/. This site shows you the sexual offenders in your area; however, you will need to check the current status of those offenders with the authorities and any details of the crime. I also suggest that you meet all of your potential neighbors and ask questions about safety. Your realtor can accompany you while you ask questions. I introduce my client to the neighbors, and then step away to let my client ask questions.
My general advice on staying safe: interior lots in a subdivision are safer than the isolated ones that back up to woods, proper street lighting helps deter crime, house alarms deter crime, neighborhood watch programs deter crime, good working locks on doors & windows deter crime, dogs deter crime.
In summary, I can not directly answer your question by law. I suggest that you get a realtor to show you a broad variety of houses, and one that can introduce you to hard working policemen, attorneys, mortgage lenders, surveyors, contractors, inspectors, and insurance agents. Realtors make important connections for their clients.