To improve a weak thesis statement, try revising it using your thesis question. Crime is dangerous to local communities. Local communities are working to solve the problem of crime. Civil liberties groups are concerned about the effects of such efforts. Find the better verb, it is often in the sentence as written.
Crime endangers local communities.
The complexity of local crime problems makes it difficult to sort out its causes. It's the number of them that cause the problem. Make A Flat Sentence Interesting. Look carefully at your sentences. Try giving a couple of your sentences some dimension be making one clause dependent, or use a transitional word to make the sentence more complex.